Method and apparatus for acquiring physical information, method for manufacturing semiconductor device including array of plurality of unit components for detecting physical quantity distribution, light-receiving device and manufacturing method therefor, and solid-state imaging device and manufacturing method therefor

ABSTRACT

Method and apparatus for acquiring physical information, method for manufacturing semiconductor device including array of a plurality of unit components for detecting physical quantity distribution, light-receiving device and manufacturing method therefor, and solid-state imaging device and manufacturing method therefore are provided. The method for acquiring physical information uses a device for detecting a physical distribution, the device including a detecting part for detecting an electromagnetic wave and a unit signal generating part for generating a corresponding unit signal on the basis of the quantity of the detected electromagnetic wave. The detecting part includes a stacked member having a structure in which a plurality of layers having different refractive indexes between the adjacent ones and each having a predetermined thickness is stacked, the stacked member being provided on the incident surface side to which the electromagnetic wave is incident and having the characteristic that a predetermined wavelength region component of the electromagnetic wave is reflected, and the remainder is transmitted.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention claims priority to Japanese Patent Application JP2004-358139 filed in the Japanese Patent Office on Dec. 10, 2004,Japanese Patent Application JP 2005-209409 filed in the Japanese PatentOffice on Jul. 20, 2005, and Japanese Patent Application JP 2004-371602filed in the Japanese Patent Office on Dec. 22, 2004, the entirecontents of which are incorporated herein by reference.

BACKGROUND

The present invention relates to a method and apparatus for acquiringphysical information, and a method for manufacturing a semiconductordevice including an array of a plurality of unit components, fordetecting a physical quantity distribution. More specifically, theinvention relates to a signal acquisition technique suitably applied toa solid-state imaging device using a semiconductor device for detectinga physical quantity distribution, the semiconductor device including anarray of a plurality of unit components sensitive to electromagneticwaves input from the outside, e.g., light and radiations, so that aphysical quantity distribution converted into electric signals by theunit components may be read out as the electric signals. In particular,the invention relates to an imaging device which permits imaging with awavelength component (for example, infrared light) other than visiblelight.

The invention also relates to a light-receiving device and a solid-stateimaging device each including photoelectric transducers formed in asemiconductor layer of silicone, a compound semiconductor, or the like,and methods for manufacturing the respective devices.

Semiconductor devices for detecting a physical quantity distribution areused in various fields, the semiconductor devices each including a lineor matrix array of a plurality of unit components (for example, pixels)sensitive to changes in physical quantities such as electromagneticwaves input from the outside, such as light and radiations.

For example, in the field of video apparatuses, CCD (Charge CoupledDevice), MOS (Metal Oxide Semiconductor), or CMOS (Complementary MetalOxide Semiconductor) solid-state imaging devices for detecting changesof light (an example of electromagnetic waves) as an example of physicalquantities are used. In these devices, a physical quantity distributionconverted into electric signals by unit components (e.g., pixels in asolid-state imaging device) is read out as the electric signals.

For example, a solid-state imaging device detects an electromagneticwave input from the outside, such as light or a radiation, usingphotodiodes serving as photoelectric transducers (light-receivingdevice; photosensors) provided in an imaging portion (pixel portion) ofthe device, thereby generating and accumulating signal charges. Theaccumulated signal charges (photoelectrons) are read out as imageinformation.

In recent years, structures for visible light imaging and infrared lightimaging have been proposed (refer to, for example, Japanese UnexaminedPatent Application Publication Nos. 2004-103964, 10-210486, 2002-369049,6-121325, 9-166493, 9-130678, and 2002-142228). For example, an infraredluminous point is previously prepared so that the position of theinfrared luminous point in a visible light image may be detected bytracking the infrared luminous point. In addition, for example, even inthe night without visible light, a clear image may be obtained byimaging with infrared irradiation. Furthermore, the sensitivity may beimproved by taking in infrared light in addition to visible light.

The structure disclosed in Japanese Unexamined Patent ApplicationPublication No. 2004-103964 is a single plate type using changes inabsorption coefficient with wavelength in the depth direction of asemiconductor.

The structures disclosed in Japanese Unexamined Patent ApplicationPublication Nos. 10-210486, 2002-369049, and 6-121325 are each amulti-plate type using a wavelength resolving optical system including awavelength separation mirror and prism as an input optical system sothat visible light and infrared light are received by respective imagingdevices.

The structure disclosed in Japanese Unexamined Patent ApplicationPublication No. 9-166493 is a single-plate type using a rotatingwavelength resolving optical system as an input optical system so thatvisible light and infrared light are received by the same imagingdevice. For example, when an infrared cut filter is inserted/extractedby a rotating mechanism, with the infrared cut filter inserted, avisible color image is output without being influenced by near-infraredlight and infrared light, while with the infrared cut filter extracted,an image with light intensity including visible light intensity andnear-infrared light intensity is output.

The structure disclosed in Japanese Unexamined Patent ApplicationPublication No. 9-130678 uses a diaphragm optical system having awavelength resolving function as an input optical system so that visiblelight and infrared light are received by the same imaging device.

The structure disclosed in Japanese Unexamined Patent ApplicationPublication No. 2002-142228 includes an imaging device sensitive tovisible light and near-infrared light, in which four types of colorfilters having respective filter characteristics are regularly disposedon pixels, and a visible color image and a near-infrared light image areindependently determined by matrix-calculation of the outputs of therespective pixels on which the four types of color filters are disposed.

A solid-state imaging device includes photoelectric transducers formedin a semiconductor layer.

Therefore, the solid-state imaging device has the problem of generatinga so-called dark current due to the surface level of the semiconductorlayer in which the photoelectric transducers are formed.

As shown in a potential diagram of FIG. 60A, the dark current is mainlygenerated by the phenomenon that electrons trapped at the surface levelare thermally exited to a conduction band and thus moved to the n-typesemiconductor region of a photodiode constituting each photoelectrictransducer by the electric field of a surface depletion layer.

For example, in a semiconductor layer composed of silicon, the band gapis 1.1 eV, and the surface level (and the Fermi level) is present at aposition where the band gap is divided at 2:1 by the Bardeen limit.

Therefore, the potential barrier against the electrons trapped at thesurface level is 0.7 eV.

Therefore, in order to decrease the dark current due to the surfacelevel, a method of forming a p+ layer on a surface of a photodiode isused (refer to, for example, Japanese Unexamined Patent ApplicationPublication No. 2002-252342, FIG. 5).

This method suppresses the dark current to some extent.

Namely, as shown in a potential diagram of FIG. 60B, the potentialbarrier against the electrons trapped at the surface level becomes 1.0eV due to the presence of the p+ layer. In other words, the potentialbarrier is increased by about 0.3 eV as compared with a case in whichthe p+ layer is absent, and thus the number of electrons thermallyexited may be decreased to decrease the dark current.

When a p+ layer is provided on a surface of a silicon substrate, thequantity of the dark current at room temperature (T=300K) estimated froma Fermi-Dirac distribution function is decreased by four digits, ascompared with a case in which the p+ layer is absent.

A Fermi-Dirac distribution function is represented by the followingequation 10:

$\begin{matrix}{{f( {E,T} )} = \frac{1}{1 + {\mathbb{e}}^{\frac{E - E_{F}}{kT}}}} & {{Equation}\mspace{14mu} 10}\end{matrix}$

wherein E is energy, EF is Fermi energy, T is an absolute temperature, kis the Boltzmann constant, e is a natural logarithm, and E-EFcorresponds to the magnitude of a potential barrier.

FIGS. 53A and 53B are drawings illustrating the structure of a sensordisclosed in Japanese Unexamined Patent Application Publication No.2004-103964, in which FIG. 53A is a drawing showing the light absorptionspectral characteristics of semiconductor layers, and FIG. 53B is aschematic drawing showing a sectional structure of a device.

In this structure, the light absorption coefficient of a Si (silicon)semiconductor decreases in the order of blue, green, red, and infraredlight, as shown in FIG. 53A. Namely, with respect to blue light, greenlight, red light, and infrared light contained in incident light L1, byusing the position dependency of wavelength in the depth direction of asemiconductor, layers for detecting visible light (blue, green, and red)and infrared light, respectively, are provided in order in the depthdirection from a surface of the Si semiconductor as shown in FIG. 53B.

However, in the structure disclosed in Japanese Unexamined PatentApplication Publication No. 2004-103964 which utilizes variations inabsorption coefficient with wavelengths, red light and green light areabsorbed by a layer for detecting blue light to some extent when beingpassed through this layer and are thus detected as blue light althoughthe quantity of theoretically detectable light is not decreased.Therefore, even when there is no original signal of blue light, signalsof green light and red light are entered to enter a signal of bluelight, thereby producing an alias and thus failing to achieve sufficientcolor reproducibility.

In order to avoid this problem, correction is preferably performed bysignal calculation processing for the entire of the three primarycolors, and thus a circuit for calculation is separately provided.Accordingly, a circuit configuration is complicated and increased inscale, and the cost is also increased. Furthermore, for example, whenone of the three primary colors is saturated, the original value of thesaturated light is not determined to cause error in the calculation. Asa result, signals are processed so as to produce a color different fromthe original color.

As shown in FIG. 53A, most semiconductors have absorption sensitivity toinfrared light. Therefore, for example, in a solid-state imaging device(image sensor) using a Si semiconductor, an infrared cut filter made ofglass is preferably inserted as an example of subtractive color filtersin front of the sensor.

Therefore, in order to take an image by receiving only infrared light orvisible light and infrared light as signals, preferably, the infraredcut filter is removed or the cut ratio of infrared light is decreased.

However, in such a case, infrared light is mixed with visible light andincident on a photoelectric transducer, thereby producing a visiblelight image with a color tone different from the original tone. It maybe thus difficult to separately produce a proper visible light image anda proper image of infrared light alone (or mixture of infrared light andvisible light) at the same time.

Apart from the above-described problem, in ordinary solid-state imagingdevices, visible light is also cut to some extent by using the infraredcut filter, thereby decreasing sensitivity. The cost is also increasedby using the infrared cut filter.

In the structures disclosed in Japanese Unexamined Patent ApplicationPublication Nos. 10-210486, 2002-369049, and 6-121325, the input opticalsystem is increased in scale by the wavelength resolution optical systemincluding a mirror and a prism for wavelength separation.

In the structure of Japanese Unexamined Patent Application PublicationNo. 9-166493, a device is increased in scale by the infrared cut filterinsertion/extraction mechanism, and the infrared cut filter is notautomatically operated.

In the structure of Japanese Unexamined Patent Application PublicationNo. 9-130678, a device is increased in scale by the diaphragm opticalsystem having a wavelength resolving function. In addition, althoughboth an infrared light image and a visible light image may besimultaneously obtained, only electric composite signals of the visiblelight image and the infrared light image are output from the imagesensor, thereby failing to output only the visible light image or onlythe infrared light image.

On the other hand, in the structure of Japanese Unexamined PatentApplication Publication No. 2002-142228, wavelength separation isperformed using the four types of color filters. Therefore, thisstructure has a problem with arithmetic processing but not have theproblem of Japanese Unexamined Patent Application Publication Nos.10-210486, 2002-369049, 6-121325, 9-166493, and 9-130678 in which theinput optical system is increased in scale. Namely, in the structure ofUnexamined Patent Application Publication No. 2002-142228, a visiblecolor image and a near-infrared light image are independently determinedby matrix operation of the outputs of the pixels on which the four typesof color filters having respective filter characteristics arerespectively disposed, and thus a visible light image and an infraredlight image may be separately and simultaneously output. However, evenwhen a visible light image is obtained, arithmetic processing isperformed between visible light and infrared light components, therebysignificantly increasing arithmetic processing as a whole.

SUMMARY

It is desirable to provide a new mechanism which may resolve at leastone of the above-mentioned problems, and a method for manufacturing adevice used in the mechanism.

According to an embodiment of the invention, there is provided animaging device having a new mechanism in which a visible color image anda near-infrared light image are independently obtained using the sameimage sensor.

According to another embodiment of the invention, there is provided amechanism in which when a visible light image and an infrared lightimage are simultaneously taken using the same image sensor, the problemthat a color tone different from an original tone is produced byremoving an infrared cut filter is resolved to permit visible lightimaging and infrared and ultraviolet light imaging with a correct colortone at the same time.

According to a still another embodiment of the invention, there isprovided a mechanism for resolving the problem that the cost isincreased by using a thick infrared cut filter made of glass as in anordinary image sensor.

On the other hand, the quantity of light received by a photodiode ofeach pixel is decreased as pixels are increasingly made fine, and thusan amount of signals is also decreased to relatively decrease the S/Nratio.

Therefore, even when the p+ layer is provided on a surface of a siliconsubstrate, for decreasing the dark current by four digits, asatisfactory S/N ratio may not be obtained. For example, even in imagingthe night sky, dot-like noise occurs in the obtained image.

In this case, when the quantity of incident light is small, in order tocompensate low sensitivity, the gain of an image signal is generallyincreased by an amplifier or the like to increase the signal intensity.However, the intensity of noise is also increased at the same time asthe signal intensity, resulting in the occurrence of significant noisein the image.

Since the signal intensity will decrease with refining in the future,noise due to the dark current is not sufficiently decreased only byproviding a p+ layer on a surface of a silicon substrate.

Therefore, it is desirable to provide a novel mechanism for securing asufficient S/N ratio.

In a light-receiving device including photodiodes includingphotoelectric transducers formed in a semiconductor layer, as well as ina solid-state imaging device, the S/N ratio decreases as refining of thelight-receiving device is advanced, and thus signals obtained byphotoelectric transfer may not be satisfactorily detected.

According to a further embodiment of the invention, there are provided alight-receiving device capable of securing a satisfactory S/N ratio bydecreasing noise due to a dark current, a process for manufacturing thelight-receiving device, a solid-state imaging device, and a process formanufacturing the same.

A method and apparatus for acquiring physical information according toan embodiment of the invention use a stacked film having a structure inwhich a plurality of layers having different refractive indexes isstacked, for separating wavelengths into a transmitted wavelength regioncomponent and a reflected wavelength region component, so that signalsof both components are independently or simultaneously acquired byseparate detecting parts.

In other words, the method for acquiring physical information uses adevice for detecting a physical quantity distribution for apredetermined purpose on the basis of unit signals, the deviceincluding, as unit components, a detecting part for detecting anelectromagnetic wave and a unit signal generating part for generating acorresponding unit signal on the basis of the quantity of the detectedelectromagnetic wave and outputting the unit signal, and the unitcomponents being disposed on the same substrate in a predeterminedorder. The detecting part includes a stacked member provided on theincident surface side on which the electromagnetic wave is incident, thestacked member having the characteristic that a predetermined wavelengthregion component of the electromagnetic wave is reflected, and theremainder is transmitted, and also having a structure in which aplurality of layers having different refractive indexes between theadjacent ones and each a predetermined thickness is stacked.

The transmitted wavelength region component transmitted through thestacked member is detected by the detecting part, and physicalinformation for a predetermined purpose is acquired on the basis of theunit signal of the transmitted wavelength region component obtained fromthe unit signal generating part.

The term “remainder” means components actually not containing at leastthe reflected wavelength region component, not all wavelength componentsexcluding the reflected wavelength region component. The sentence“actually not containing the reflected wavelength region component”means that there is substantially no influence of the reflectedwavelength region component, and the influence of the reflectedwavelength region component may be slightly present. This is becausewith respect to the transmitted wavelength side, it is sufficient toacquire a signal in which the influence of the reflected wavelengthregion is negligible. Also, with respect to the reflected wavelengthregion, it is sufficient to acquire a signal in which the influence ofthe transmitted wavelength region is negligible.

The apparatus for acquiring physical information is suitable forcarrying out the method for acquiring physical information. Theapparatus includes a stacked member disposed on the incident surfaceside of a detecting part on which an electromagnetic wave is incident,and a signal processing unit for acquiring physical information for apredetermined purpose on the basis of a unit signal of a transmittedwavelength region component detected by the sensing part and transmittedthrough the stacked member, the unit signal being obtained from a unitsignal generating part on the basis of the transmitted wavelength regioncomponent. The stacked member has a structure in which a plurality oflayers having different refractive indexes between the adjacent ones andeach a predetermined thickness is stacked, and also has thecharacteristic that a predetermined wavelength region component of theelectromagnetic wave is reflected, and the remainder is transmitted. Thestacked member may be separated from the detecting part, but ispreferably integrated with the detecting part.

A method for manufacturing a semiconductor device according to anembodiment of the invention is suitably used for manufacturing theabove-described device. The method includes the steps of forming asemiconductor element layer having a detecting part and a unit signalgenerating part on a semiconductor substrate; forming a wiring layer forforming signal lines on the semiconductor element layer, for readingunit signals from the unit signal generating part; and forming a stackedfilm on the wiring layer, the stacked film having a structure in which aplurality of layers having different refractive indexes between theadjacent ones and each a predetermined thickness is stacked, and havingthe characteristic that a predetermined wavelength region component ofan electromagnetic wave is reflected, and the remainder is transmitted.

In order to permit detection of the reflected wavelength regioncomponent, the method may further include a step of regularly removing aportion of the stacked film in position alignment with a plurality ofdetecting parts corresponding to respective wavelengths. In this case,the transmitted wavelength region component transmitted through thestacked film is detected by one of the plurality of detecting parts, andthe reflected wavelength region component not transmitted through thestacked film is detected by the other of the plurality of detectingparts. From the viewpoint that a portion of the stacked film isregularly removed in position alignment with the plurality of detectingparts corresponding to respective wavelengths, the stacked film ispreferably integrated with the detecting parts rather than beingseparated from the detecting parts.

In application to color imaging, the method may further include a stepof forming optical members for respective wavelengths on the stackedfilm in position alignment with pixels corresponding to the respectivewavelengths, for transmitting a predetermined wavelength component ofthe transmitted wavelength region component. From the viewpoint that theoptical members for respective wavelengths are formed in positionalignment with the detecting parts corresponding to the respectivewavelengths, the optical members for respective wavelengths arepreferably integrated with the stacked film and the detecting partsrather than being separated from the stacked film and the detectingparts.

The further characteristics of the invention will be described below.

For example, in order to acquire an image about a reflected wavelengthregion component such as infrared light relative to a transmittedwavelength region component such as visible light, a stacked member isnot provided on the incident surface side of a detecting part for thereflected wavelength region component to which an electromagnetic waveis incident so that the reflected wavelength region component isdetected by the detecting part, and thus physical information for asecond predetermined purpose may be obtained on the basis of a unitsignal of the reflected wavelength region component obtained from a unitsignal generating part.

Also, one of first physical information based on a unit signal of thetransmitted wavelength region component and second physical informationbased on a unit signal of the reflected wavelength region component maybe selected and output, or both may be simultaneously output.

Furthermore, optical members may be provided on the respective incidentsides of the plurality of detecting parts for detecting the transmittedwavelength region component, for separating the transmitted wavelengthregion component into respective wavelength region components, and therespective transmitted wavelength region components may be detected bythe plurality of detecting parts, respectively. In this case, otherphysical information on the transmitted wavelength region component maybe acquired by combining the unit signals of the respective transmittedwavelength region components, which are obtained from the unit signalgenerating part. For example, a color image may be taken using, as theoptical members, primary color filters in which transmitted light in thevisible region has the wavelength components of the three primarycolors, or complementary color filters in which transmitted light in thevisible region has complementary colors of the respective three primarycolors.

In order to acquire a signal of the reflected wavelength regioncomponent, not only the reflected wavelength region component but alsothe whole or part (e.g., the wavelength component of one of the threeprimary colors) of the transmitted wavelength region component may besimultaneously loaded by the detecting parts, and a signal of only thereflected wavelength region component in which the influence of thetransmitted wavelength region component may be neglected may be acquiredby differential arithmetic operation. Alternatively, an optical memberfor transmitting the reflected wavelength region component and cuttingoff the transmitted wavelength region component may be provided on theincident surface side of the detecting part for the reflected wavelengthregion component so as to prevent the incidence of the transmittedwavelength region component.

When a signal of the reflected wavelength region component is alsoacquired to form an image, a general arrangement for the detecting partfor detecting the transmitted wavelength region component is preferablypartially replaced by a detecting part for detecting the reflectedwavelength region component. In this case, resolution may be affected bythe arrangement of each of the detecting parts.

From this viewpoint, for example, when the resolution of an ordinarycolor image based on the transmitted wavelength region component isgiven greater importance, detecting elements (typically pixels for colorG) for detecting a predetermined wavelength component in a plurality ofdetecting elements for respective colors which contribute to formationof the ordinary color image may be arranged in a checked pattern. On theother hand, when the resolution of an image (typically an infraredimage) based on the reflected wavelength region component is givengreater importance, the detecting part contributing formation of thisimage may be formed in a checked pattern.

When the pixels are arranged in a two-dimensional lattice form, anoblique lattice form rotated at a predetermined angle (typically about45 degrees) is more preferred than a square lattice form in which thepixels are arranged in directions parallel and perpendicular to thevertical and horizontal reading directions, respectively. This isbecause the pixel densities in the vertical and horizontal directionsare increased to further increase the resolutions in these directions.

A light receiving device according to an embodiment of the inventionincludes a photoelectric transducer formed in a semiconductor layer, anda single crystal layer formed on a portion of the semiconductor layer inwhich at least the photoelectric transducer is formed, the singlecrystal layer being composed of a material having a wider band gap thanthat of the semiconductor layer.

In the above-described light-receiving device, the single crystal layeris formed on a portion of the semiconductor layer in which at least thephotoelectric transducer is formed, the single crystal layer beingcomposed of a material having a wider band gap than that of thesemiconductor layer. Therefore, the single crystal layer has a widerband gap, and thus the barrier against electrons at the surface level isincreased, thereby decreasing the dark current due to the electrons.

A method for manufacturing a light-receiving device, which includes aphotoelectric transducer formed in a semiconductor layer, includes astep of forming a single crystal layer on a portion of the semiconductorlayer in which at least the photoelectric transducer is formed, thesingle crystal layer being composed of a material having a wider bandgap than that of the semiconductor layer.

In the method for manufacturing the light-receiving device, the methodincluding the step of forming the single crystal layer on a portion ofthe semiconductor layer in which at least the photoelectric transduceris formed, the single crystal layer being composed of a material havinga wider band gap than that of the semiconductor layer, the barrieragainst electrons at the surface level is increased by the singlecrystal layer, thereby decreasing the dark current due to the electrons.

A solid-state imaging device according to an embodiment of the inventionincludes a photoelectric transducer formed in a semiconductor layer, anda single crystal layer formed on a portion of the semiconductor layer inwhich at least the photoelectric transducer is formed, the singlecrystal layer being composed of a material having a wider band gap thanthat of the semiconductor layer.

In the above-described solid-state imaging device, the single crystallayer is formed on a portion of the semiconductor layer in which atleast the photoelectric transducer is formed, the single crystal layerbeing composed of a material having a wider band gap than that of thesemiconductor layer. Therefore, the single crystal layer has a widerband gap, and thus the barrier against electrons at the surface level isincreased, thereby decreasing the dark current due to the electrons.

A method for manufacturing a solid-state imaging device, which includesa photoelectric transducer formed in a semiconductor layer, includes astep of forming a single crystal layer on a portion of the semiconductorlayer in which at least the photoelectric transducer is formed, thesingle crystal layer being composed of a material having a wider bandgap than that of the semiconductor layer.

In the method for manufacturing the solid-state imaging device, themethod including the step of forming the single crystal layer on aportion of the semiconductor layer in which at least the photoelectrictransducer is formed, the single crystal layer being composed of amaterial having a wider band gap than that of the semiconductor layer,the barrier against electrons at the surface level is increased by thesingle crystal layer, thereby decreasing the dark current due to theelectrons.

According to an embodiment of the invention, a transmitted wavelengthregion component and a reflected wavelength region component areseparated into the respective wavelengths using a stacked film having astructure in which a plurality of layers having different refractiveindexes is stacked, and signals of both components are detected byrespective detecting parts.

Therefore, in a single semiconductor device (e.g., an image sensor),physical information on the transmitted wavelength region component maybe acquired, in which the influence of the reflected wavelength regioncomponent may be neglected. In this case, for example, an expensiveoptical member made of glass for cutting off infrared light may not beprovided for cutting off infrared light which is the reflectedwavelength region component relative to visible light which is anexample of the transmitted wavelength region component. Therefore,variations in absorption coefficient with wavelength in the depthdirection of a semiconductor are not used, and thus a problem with colorreproducibility due to the variations does not occur.

When the transmitted wavelength region component and the reflectedwavelength region component are separately detected to simultaneouslyobtain signal outputs of both components, with respect to thetransmitted wavelength region component, the reflected wavelength regioncomponent is previously cut off by the stacked film. Therefore, unlikein the structure disclosed in Japanese Unexamined Patent ApplicationPublication No. 2002-142228, arithmetic operation between thetransmitted wavelength region component and the reflected wavelengthregion component may not be performed for obtaining a signal of thetransmitted wavelength region component which is not influenced by thereflected wavelength region component at all.

Of course, signals of the transmitted wavelength region component andthe reflected wavelength region component may be separated andsimultaneously detected, and thus visible imaging and infrared andultraviolet imaging may be simultaneously performed, for example, usinga structure for separately detecting infrared-ultraviolet light andvisible light. In this case, when visible light is further divided intosignal components of the primary colors and then detected, a visiblelight image with a correct color tone and an infrared-ultraviolet imagemay be simultaneously taken.

Furthermore, the barrier against electrons at the surface level isincreased by the single crystal layer, thereby decreasing the darkcurrent due to the electrons. For example, the dark current may besignificantly decreased by 12 digits to significantly improve the signalS/N ratio with incident light.

Consequently, under imaging conditions, such as a small quantity ofincident light in a dark room or the like, even when the signal gain isset to a higher value for increasing sensitivity, an image withoutsignificant noise may be obtained.

Furthermore, even in an imaging device with low sensitivity, a highquality image may be obtained only by amplification with an amplifierregardless of the quantity of incident light.

Furthermore, even when the quantity of incident light is increased byrefining of elements, a sufficient S/N ratio may be attained, and thus asatisfactory image without significant noise may be obtained only byamplification with an amplifier for compensating for the lowsensitivity.

Therefore, the number of pixels in a solid-state imaging device may beincreased by refining of elements, and an optical device and asolid-state imaging device each including a light-receiving device maybe decreased in size.

Additional features and advantages are described herein, and will beapparent from, the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a drawing illustrating the concept of a spectral image sensorfor dispersing an electromagnetic wave into predetermined wavelengthsusing a dielectric stacked film.

FIG. 2 is a conceptual drawing illustrating the basic configuration of aspectral image sensor using a dielectric stacked film.

FIG. 3 is a drawing showing an example of a configuration in which thebasic configuration of the spectral image sensor shown in FIG. 2 isapplied to multi-wavelength spectral separation.

FIG. 4 is a structural drawing illustrating the basic concept of amethod for designing a stacked film.

FIG. 5 is a reflection spectrum atlas illustrating the basic concept ofa method for designing a stacked film.

FIG. 6 is a reflection spectrum atlas illustrating the basic concept ofa method for designing a stacked film.

FIGS. 7A and 7B are drawings (conceptual drawings of reflectionspectrum) illustrating conditions of reflection center wavelength λ.

FIG. 8 is a reflection spectrum atlas illustrating conditions ofreflection center wavelength λ.

FIG. 9 is a reflection spectrum atlas illustrating conditions ofreflection center wavelength λ.

FIG. 10 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to a first embodiment of the invention.

FIG. 11 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the first embodiment of the invention.

FIG. 12 is a reflection spectrum atlas (detailed reflection spectrumatlas) illustrating a spectral image sensor corresponding tosingle-wavelength spectral separation using a stacked film according tothe first embodiment of the invention.

FIG. 13 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the first embodiment of the invention.

FIG. 14 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the first embodiment of the invention.

FIG. 15 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to a second embodiment of the invention.

FIG. 16 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the second embodiment of the invention.

FIG. 17 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the second embodiment of the invention.

FIG. 18 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the second embodiment of the invention.

FIG. 19 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to a third embodiment of the invention.

FIG. 20 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the third embodiment of the invention.

FIG. 21 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the third embodiment of the invention.

FIG. 22 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the third embodiment of the invention.

FIG. 23 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the third embodiment of the invention.

FIG. 24 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the third embodiment of the invention.

FIG. 25 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to a fourth embodiment of the invention.

FIG. 26 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the fourth embodiment of the invention.

FIG. 27 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to a fifth embodiment of the invention.

FIG. 28 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the fifth embodiment of the invention.

FIGS. 29A and 29B are drawings illustrating a circuit (corresponding toR, G, B, and infrared light IR) in the application of a stacked film toan IT_CCD image sensor.

FIG. 30 is a drawing illustrating a circuit (corresponding to visiblelight VL and infrared light IR) in the application of a stacked film toan IT_CCD image sensor.

FIGS. 31A and 31B drawings illustrating a circuit (corresponding to R,G, B, and infrared light IR) in the application of a stacked film to aCMOS image sensor.

FIG. 32 is a drawing illustrating a circuit (corresponding to visiblelight VL and infrared light IR) in the application of a stacked film toa CMOS image sensor.

FIG. 33A to 33F are drawings illustrating an example of a process formanufacturing a spectral image sensor.

FIG. 34 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to a sixth embodiment of the invention.

FIG. 35 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the sixth embodiment of the invention.

FIG. 36 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the sixth embodiment of the invention.

FIG. 37 is a structural drawing illustrating a spectral image sensorcorresponding to single-wavelength spectral separation using a stackedfilm according to the sixth embodiment of the invention.

FIG. 38 is a drawing illustrating a spectral image sensor correspondingto single-wavelength spectral separation using a stacked film accordingto the sixth embodiment of the invention.

FIG. 39 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the sixth embodiment of the invention.

FIG. 40 is a reflection spectrum atlas illustrating a spectral imagesensor corresponding to single-wavelength spectral separation using astacked film according to the sixth embodiment of the invention.

FIGS. 41A, 41B, and 41C are drawings showing examples of an arrangementof color separation filters.

FIG. 42 is a drawing (perspective view) illustrating an example of aconfiguration of a CCD solid-state imaging device having thearrangements of color separation filters shown in FIGS. 41A, B, and C.

FIG. 43 is a drawing (sectional structural drawing) illustrating anexample of a configuration of a CCD solid-state imaging device capableof separately imaging the two wavelength components, i.e., infraredlight and visible light, at the same time.

FIGS. 44A, 44B, and 44C are drawings showing other examples of anarrangement of color separation filters.

FIG. 45 is a drawing (perspective view) illustrating an example of aconfiguration of a CCD solid-state imaging device having thearrangements of color separation filters shown in FIGS. 44A, B, and C.

FIGS. 46A and 46B are drawings illustrating a first example of pixelarrangements conscious of a decrease in resolution.

FIG. 47 is a diagram showing an example of the transmission spectralcharacteristics of a black filter.

FIGS. 48A and 48B are drawings illustrating a second example of pixelarrangements conscious of a decrease in resolution.

FIGS. 49A, 49B, and 49C are drawings illustrating a third example ofpixel arrangements conscious of a decrease in resolution.

FIGS. 50A and 50B are drawings illustrating a fourth example of pixelarrangements conscious of a decrease in resolution.

FIGS. 51A and 51B are drawings illustrating a fifth example of pixelarrangements conscious of a decrease in resolution.

FIGS. 52A and 52B are drawings illustrating a sixth example of pixelarrangements conscious of a decrease in resolution.

FIGS. 53A and 53B are drawings illustrating the structure of a sensordisclosed in Japanese Unexamined Patent Application Publication No.2004-103964.

FIG. 54 is a schematic drawing (schematic plan view) showing theconfiguration of a solid-state imaging device according to a seventhembodiment of the invention.

FIG. 55 is a sectional view of the solid-state imaging device shown inFIG. 54.

FIG. 56 is a diagram showing a potential distribution.

FIG. 57 is a schematic drawing (sectional view) showing theconfiguration of a solid-state imaging device according to anotherembodiment of the invention.

FIG. 58 is a schematic drawing (sectional view) showing theconfiguration of a solid-state imaging device including a single crystallayer formed by a method different from that used for the solid-stateimaging device shown in FIG. 57.

FIG. 59 is a schematic drawing (schematic plan view) showing theconfiguration of a solid-state imaging device according to a furtherembodiment of the invention.

FIG. 60A is a diagram showing a potential distribution of a generalsolid-state imaging device.

FIG. 60B is a diagram showing a potential distribution of a structureincluding a p+ layer formed on a surface.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in detail belowwith reference to the drawings.

<<Concept of Dielectric Stacked Film Image Sensor>>

FIG. 1 is a drawing illustrating the concept of a spectral image sensorin which an electromagnetic wave is dispersed into predeterminedwavelengths using a dielectric stacked film. Herein, description is madeof a spectral image sensor in which light as an example ofelectromagnetic waves is dispersed into predetermined wavelengths.

In FIG. 1, reference numeral 1 denotes a dielectric stacked film, andreference numeral 10 denotes a spectral filter.

As shown in FIG. 1, the dielectric stacked film 1 is a stacked memberhaving a structure in which a plurality of layers having different(refractive index difference Δn) refractive indexes nj (wherein j is apositive integer of 2 or more) between the adjacent ones and each havinga predetermined thickness dj is stacked. As a result, the dielectricstacked film 1 has the characteristic that a predetermined wavelengthregion component of an electromagnetic wave is reflected, and theremainder is transmitted, as described below.

The dielectric layers 1_j constituting the dielectric stacked film 1 arecounted, for example, from the first layer to the kth layer sideexcluding the thick layers (layers 1_0 and 1_k) on both sides. Thedielectric stacked film 1 substantially includes the layers excludingthe thick layers (layers 1_0 and 1_k) on both sides.

When light is incident on the dielectric stacked film 1 having theabove-described structure, the reflectance (or transmittance) assumessome dependency on wavelength λ due to interference in the dielectricstacked film 1. This effect becomes significant as the refractive indexdifference Δn of light increases.

In particular, when the dielectric stacked film 1 has a periodicstructure or a certain condition (for example, the condition d˜λ/4n ofthe thickness d of each layer), of incident light L1 such as white lightor the like, the reflectance of light in a specified wavelength region(specified wavelength region light) is effectively increased to mainlyproduce a reflected light component L2. Namely, the transmittance isdecreased. The reflectance of light in the other wavelength regions isdecreased to mainly produce a transmitted light component L3. In otherwords, the transmittance may be increased.

The wavelength λ is a center wavelength of a certain wavelength region,and n is the refractive index of a layer. In an embodiment of theinvention, the spectral filter 10 is realized by utilizing thewavelength dependency of reflectance (or transmittance) in thedielectric stacked film 1.

<Basic Structure of Spectral Image Sensor Using Dielectric Stacked Film>

FIG. 2 is a conceptual drawing illustrating the basic structure of aspectral image sensor using a dielectric stacked film. FIG. 2 shows anexample in which incident light is dispersed into infrared light IR(Infrared) and visible light VL (Visible Light). The dielectric stackedfilm 1 is formed so as to have high reflectance for infrared light IR atwavelength λ (mainly a wavelength side longer than 780 nm) in theinfrared region longer than that of visible light VL. In this case,infrared light IR is cut off. When such a dielectric stacked film 1 isnot formed, infrared light IR may be transmitted.

Since the dielectric stacked film 1 includes a plurality of layers, atleast two types of members (layer materials) are used for the respectivedielectric layers 1_j. When three or more layers are used, differentlayer materials may be used for the respective dielectric layers 1_j ortwo (or more) layers may be stacked alternately or in any desired order.Alternatively, the dielectric stacked film 1 may include first andsecond basic layer materials and may be partially replaced by a third(or more) layer material. This will be described in detail below.

<Structure of Multi-wavelength Spectral Image Sensor Using DielectricStacked Film>

FIG. 3 is a drawing illustrating an example of a structure in which thebasic structure of a spectral image sensor 11 including the spectralimage sensor 10 shown in FIG. 2 is applied to multi-wavelengthseparation.

In FIG. 3, reference numeral 1 denotes a dielectric stacked film;reference numeral 11, a spectral image sensor; and reference numeral 12,a unit pixel matrix.

As described with reference to FIG. 2, infrared light IR is cut off byforming the dielectric stacked film 1, and infrared light IR istransmitted without forming the dielectric stacked film 1. By using thisfact, a portion of the dielectric stacked film 1 is regularly removed inposition alignment with a plurality of detecting parts (e.g.,photodiodes) corresponding to respective wavelengths, the detectingparts constituting the unit pixel matrix 12. Namely, in each pixel(cell), infrared light is cut off or not cut off to permit imaging withonly visible light VL and imaging with only infrared light IR at thesame time or imaging with only visible light VL and imaging with amixture of infrared light IR and visible light VL at the same time.

A monochrome image or color image may be taken without being influencedby infrared light IR in the daytime or imaging with infrared light IRmay be performed in the night. According demand, both images may beoutput at the same time. In this case, an image with only infrared lightIR may be obtained without being influenced by visible light VL in thedaytime.

In other words, in the spectral image sensor 11 corresponding tomulti-wavelength spectral separation, the dielectric stacked film 1 forreflecting infrared light IR is formed on the photodiode constituting amain part of each pixel of the unit pixel matrix 12 in which the pixelsare regularly arranged so that infrared light is reflected, and amonochrome image of visible light VL alone is obtained without beinginfluenced by infrared light IR on the basis of the pixel signalsobtained from the pixels. Unlike in the structure disclosed in JapaneseUnexamined Patent Application Publication No. 2002-142228, arithmeticoperation may not be performed between visible light VL and infraredlight IR components for obtaining a monochrome image of visible light VLwith substantially no influence of infrared light IR.

Furthermore, as an example of optical members for separating awavelength region component into predetermined wavelength regioncomponents, a color filter 14 having a predetermined wavelengthtransmission characteristic in the visible light VL region may beprovided on each photodiode on which the dielectric stacked film 1 isformed. In this case, an image of only a specified wavelength region inthe visible light VL region is obtained with substantially no influenceof infrared light IR.

When color filters 14 x having different wavelength transmissioncharacteristics in the visible light VL region are regularly integrallyarranged on a plurality of the photodiodes corresponding respectivewavelengths (respective colors) in position alignment with therespective photodiodes, the photodiodes constituting the unit pixelmatrix 12, the visible light VL region may be separated into respectivewavelengths (respective colors). Consequently, a color image (visiblecolor image) of only visible light VL with substantially no influence ofinfrared light IR may be obtained by composite processing based on pixelsignals from the pixels of respective colors. Unlike in the structuredisclosed in Japanese Unexamined Patent Application Publication No.2002-142228, arithmetic operation may not be performed between visiblelight VL and infrared light IR components for obtaining a color image ofvisible light VL with substantially no influence of infrared light IR.

In the same imaging device (spectral image sensor 11), for example, whenthe unit pixel matrix 12 includes a pixel in which the dielectricstacked film 1 is not formed, a monochrome or color image of visiblelight VL and an image of infrared light IR may be always independentlyobtained by matrix operation of the outputs of the pixels. In addition,since the dielectric stacked film 1 integrally formed on each of thephotodiodes is partially removed, unlike in a case in which separateoptical members including the respective dielectric stacked films 1 butnot including the dielectric stacked film 1 are disposed on an imagingdevice, a problem with alignment does not occur.

For example, an image (monochrome image or color image) of only visiblelight VL with substantially no influence of infrared light IR and animage of a mixture of infrared light IR and visible light VL may betaken at the same time. In addition, an image of only infrared light IRwith substantially no influence of visible light VL may be taken bycomposite processing (in detail, differential processing) of a component(monochrome image component or color image component) of only visiblelight VL and a mixed component of infrared light IR and visible lightVL.

Considering that the phrase “with substantially no influence” is finallybased on a human vision, light influence may be present to an extentthat a significant difference is generally not observed with the humaneyes. In other words, with respect to the infrared light IR side, it maybe possible to obtain an infrared image (an example of physicalinformation) in which the transmitted wavelength region (visible lightVL) may be neglected. With respect to the visible light VL side, it maybe possible to obtain an ordinary image (an example of physicalinformation) in which the reflected wavelength region component(infrared light IR) may be neglected.

The color filter 14 may be an primary color filter for a blue componentB (for example, transmittance of about 1 at wavelength λ=400 to 500 nm,and transmittance of substantially zero at other wavelengths), a greencomponent G (for example, transmittance of about 1 at wavelength λ=500to 600 nm, and transmittance of substantially zero at otherwavelengths), or a red component R (for example, transmittance of about1 at wavelength λ=600 to 700 nm, and transmittance of substantially zeroat other wavelengths), the components B, G, and R being the threeprimary color components of visible light VL (wavelength λ=380 to 780nm).

Alternatively, the color filter 14 may be a complementary color filterfor a yellow component Ye (for example, transmittance of substantiallyzero at wavelength λ=400 to 500 nm, and transmittance of about 1 atother wavelengths), a magenta component Mg (for example, transmittanceof substantially zero at wavelength λ=500 to 600 nm, and transmittanceof about 1 at other wavelengths), or a cyan component Cy (for example,transmittance of substantially zero at wavelength λ=600 to 700 nm, andtransmittance of about 1 at other wavelengths). The complementary colorfilter has transmittance of substantially zero for the three primarycolor components of visible light.

The complementary color filter has higher sensitivity than that of theprimary color filter, and thus the sensitivity of an imaging device maybe increased using the complementary color filter in which transmittedlight in the visible region has the corresponding complementary color ofone of the primary colors. Conversely, use of the primary color filterhas the advantage that signals of the primary colors may be obtainedeven without differential processing, thereby simplifying signalprocessing.

The term “transmittance of about 1” indicates an ideal state in whichthe transmittance in a certain wavelength region is greatly higher thanthose in other wavelength regions. The transmittance is not necessarily“1”. Similarly, the term “transmittance of substantially zero” indicatesan ideal state in which the transmittance in a certain wavelength regionis greatly lower than those in other wavelength regions. Thetransmittance is not necessarily “substantially zero”.

In either of the primary color system and the complementary colorsystem, the wavelength region component of a predetermined color(primary color or complementary color) within the region of visiblelight VL, which is the transmitted wavelength region component, may betransmitted regardless of whether of not the region of infrared lightIR, which is the reflected wavelength region component, is passed, i.e.,regardless of the transmittance for infrared light IR. This is becausethe infrared light IR component is cut off with the dielectric stackedfilm 1.

For example, as shown in FIG. 3, the dielectric stacked film 1 is notformed only on the pixel 12IR in the unit pixel matrix 12 including thefour pixels (cells), and the dielectric stacked films 1 are formed onthe pixels 12R, 12G, and 12B of the other colors of red (R), green (G),and blue (B), respectively. Also, three primary color filters 14R, 14G,and 14B of red (R), green (G), and blue (B), respectively, are alsoprovided on the respective dielectric stacked films 1.

As shown in FIG. 3, in order to increase sensitivity, a color filter 14Cis not disposed in the pixel 12IR without the dielectric stacked film 1so that not only infrared light IR but also visible light VLsimultaneously contribute to signals. In this case, the pixel 12IR forinfrared light may be allowed to substantially function as a pixel forinfrared light IR and visible light VL, not only for infrared light IR.

In particular, the unit pixel matrix 12 including the four pixels isdivided into the pixels 12R, 12G, 12B, and 12IR so that the entirestructure of the imaging device (spectral image sensor 11) may be formedwithout any space, thereby facilitating design.

In such a case, an image is synthesized on the basis of the red (R),green (G), and blue (B) color components obtained from the three pixels12R, 12G, and 12B, respectively, and thus a visible VL color image(i.e., an ordinary color image) may be obtained with substantially noinfluence of infrared light IR. At the same time, an image of infraredlight IR may be taken on the basis of mixed components of infrared lightIR and visible light VL which are obtained from the pixel 12IR.

The term “image of infrared light IR” means an image of only infraredlight IR which is substantially not influenced by visible light VL or animage of a mixture of infrared light IR and visible light VL. In thestructure shown in FIG. 3, in order to obtain an image of only infraredlight IR which is substantially not influenced by visible light VL, itis desirable to take a difference between a component mixture ofinfrared light IR and visible light VL and each of the color componentsof red (R), green (G), and blue (B) which are obtained from the threepixels 12R, 12G, and 12B, respectively. This is because the intensity ofinfrared light is determined by subtracting the intensities of blue,red, and green, which are obtained from the three pixels 12R, 12G, and12B, respectively, from the output of the pixel 12IR which receivesvisible light VL and infrared light IR, even when a green filter 14G ora black filter 14BK is not provided, as described below.

Considering an application in which an image of only infrared light IRwith substantially no influence of visible light VL is taken at the sametime, such as an application to optical communication or an applicationin which a position is detected by tracking an infrared luminous point,a color filter 14C may be disposed on the pixel 12IR, the color filtertransmitting at least infrared light IR which is the reflectedwavelength region component and transmitting a predetermined wavelengthcomponent of visible light VL which is the transmitted wavelength regioncomponent.

For example, when a green filter 14G transmitting infrared light IR andgreen light G is provided as the color filter C, a mixture of thecomponents of infrared light IR and green visible light LG is obtainedfrom the pixel 12IR. However, by taking a difference from the greencomponent of only visible light obtained from the pixel 12G, it may bepossible to obtain an image of only infrared light with substantially noinfluence of visible light (in this case, green light G). Although thegreen filter 14G is preferably provided, processing is simplified ascompared with a case in which the intensities of blue, red, and greenobtained from the three pixels 12R, 12G, and 12B, respectively, aresubtracted without proving the green filter 14G.

Alternatively, the black filter 14BK which transmits infrared light andabsorbs only visible light VL may be provided as the color filter 14C.In this case, visible light VL is absorbed by the black filter 14BK toobtain a component of only infrared light IR from the pixel 12IR,thereby obtaining an image of only infrared light IR with substantiallyno influence of visible light VL even when differential processing isnot performed.

Each of R, G, and B color filters generally used at present has hightransmittance for R, G, or B, in the visible light band and lowtransmittance for the other colors (for example, G and B in the case ofa R color filter). However, transmittance for light out of the visiblelight band is not specific and is generally higher than that for theother colors (for example, G and B in the case of a R color filter). Forexample, each of the filters has sensitivity in the infrared region andtransmits light in the infrared region. However, in this embodiment,even when the transmittance out of the visible light band is high, thereis no influence.

<<Method for Designing a Dielectric Stacked Film; an Example of InfraredCut>>

<Method for Designing Thickness dj>

FIGS. 4 to 6 are drawings illustrating the basic concept of a method fordesigning the dielectric stacked film 1. Herein, description is made ofan example of design in which the dielectric stacked film 1 includesfirst and second basic layer materials, and infrared light IR isselectively reflected.

As shown in a structural drawing of FIG. 4, in the dielectric stackedfilm 1 used in this embodiment, a plurality of dielectric layers 1_jeach composed of a first or second layer material is stacked, thedielectric layers 1_j being held between thick silicon oxide SiO₂ layers(referred to as “SiO₂” hereinafter) on both sides (referred to as a“layer 0” on the incident side and a “layer k” on the opposite side). Inthe example shown in FIG. 4, general materials are used as the first andsecond layer materials for the dielectric layers 1_j. Specifically,silicon nitride Si₃N₄ (referred to as “SiN” hereinafter) and siliconoxide SiO₂ are used as the first layer material and the second layermaterial, respectively, and are stacked alternately. It is also assumedthat sufficiently thick layers of silicon oxide SiO₂ (do=dk=∞) aredeposited on and below the structure of the dielectric stacked film 1.

When such a dielectric stacked film 1 satisfies the equation (1), thereflectance may be effectively increased.

Equation 1dj=λ0/4nj  (1)

In this equation, dj (j is a layer number hereinafter) represents thethickness of each of the dielectric layers 1_j constituting thedielectric stacked film 1, nj represents the refractive index of each ofthe dielectric layers 1_j, and λ0 represents the center wavelength(referred to as the “reflection center wavelength” hereinafter) in thereflected wavelength region.

The dielectric layers 1_j constituting the dielectric stacked film 1 arecounted from the first layer to the kth layer excluding the thicksilicon oxide SiO₂ layers on both sides. For example, the dielectriclayers 1_j includes three layers including a SiN layer, an SiO₂ layer,and an SiN layer or five layers including an SiN layer, an SiO₂ layer,an SiN layer, an SiO₂ layer, and an SiN layer in the order from thefirst to the kth layer. FIG. 4 shows a seven-layer structure.

In addition, the reflection center wavelength λ0 of infrared light IR,which is a reflected wavelength region, is 900 nm, the refractive indexnα of silicon nitride of odd-numbered layers is 2.03, the refractiveindex nβ of silicon oxide SiO₂ of the 0th, even-numbered, and kth layersis 1.46, and the refractive index difference Δn is 0.57.

According to equation (1), the thickness dα (=d1, d3, . . . j=oddnumber) of silicon nitride SiN is 111 nm, and the thickness dβ (=d2, d4,. . . j=even number) of silicon oxide SiO₂ is 154 nm.

FIG. 5 shows the results (reflection spectrum atlas) of reflectance Rcalculated by the effective Fresnel coefficient method for the structureshown in FIG. 4 using general materials. This figure indicates thedependency of a reflection spectrum on the number of layers.

The results shown in FIG. 5 indicate that as the number of layersincreases, the reflectance R increases with a center at the reflectioncenter wavelength λ0 900 nm of infrared light IR. Furthermore, it isfound that by selecting a wavelength of 900 nm as the reflection centerwavelength λ0, infrared light IR and visible light VL are substantiallyseparated. It is further found that with five or more layers, thereflectance R is 0.5 or more, and in particular, with seven or morelayers, the reflectance R desirably exceeds 0.7.

FIG. 6 is a diagram illustrating the dependency (relation to variations)on variations in the thickness of the dielectric layers 1_j. FIG. 6shows the results (reflection spectrum atlas) calculated with changes of±10% of the thickness dj of each dielectric layer 1_j in an exampleincluding seven layers.

According to conditional equation (1), an ideal calculated value isobtained by the Fresnel coefficient method. However, in fact, thecondition of equation (1) is easy and varies. For example, it is foundfrom calculation by the Fresnel coefficient method that even when thethickness dj has an error of ±10%, the reflectance is effectivelyincreased.

For example, FIG. 6 indicates that even when the thickness dj hasvariations, the reflectance R is effectively increased. Specifically,the sufficient reflectance R of 0.5 or more is obtained at thereflection center wavelength λ0 of 900 nm of infrared light IR, and thereflectance is high over the entire infrared region IR (mainly on thewavelength side of 780 nm or longer). Therefore, when variations areactually taken into consideration, with the dielectric layers 1_j eachhaving a thickness of dj within the range of equation (2) below, asufficient effect is obtained for effectively increasing thereflectance.

Equation 20.9×λ0/4n≦dj≦1.1×λ0/4n  (2)

<Method of Designing Reflection Center Wavelength λ0>

FIGS. 7 to 9 are drawings illustrating conditions of the reflectioncenter wavelength λ0. The numerical condition of the thickness djdepends on the band width ΔλIR in the infrared reflection region of aspectrum. As shown in FIG. 7(A) showing the concept of a reflectionspectrum, when the band width ΔλIR in the infrared reflection region iswide, reflection of visible light VL becomes significant unless thecenter wavelength λ0 is shifted to the longer wavelength side. As shownin FIG. 7(B) showing the concept of a reflection spectrum, when the bandwidth ΔλIR in the infrared reflection region is narrow, reflection ofvisible light VL does not occur in the infrared region near visiblelight VL unless the center wavelength λ0 is shifted to the shorterwavelength side.

A graph of an absorption spectrum of silicon Si indicates that wheninfrared light IR in a range of 0.78 μm≦λ≦0.95 μm within the infraredregion is reflected, the infrared cut effect becomes satisfactory. Thisis because light at wavelengths longer than 0.95 μm is rarely absorbedin silicon Si and is not subjected to photoelectric conversion.Therefore, it is preferred to select the reflection center wavelength sothat infrared light IR at wavelengths in a range of 0.78 μm≦λ≦0.95 μm isreflected.

Since visible light VL in a range of 649 nm to 780 nm within the red (R)region has low visibility, an imaging device may not be influenced byreflection of the light. Therefore, even when reflection occurs in thewavelength region of 640 nm to 780 nm, no trouble occurs.

Furthermore, with the large refractive index difference Δn of thedielectric stacked film 1, the band width ΔλIR of the infraredreflection region widens, and conversely with the small refractive indexdifference Δn of the dielectric stacked film 1, the band width ΔλIR ofthe infrared reflection region narrows. Therefore, in the case of aSiN/SiO₂ multilayer film, the band width ΔλIR of the infrared reflectionregion becomes narrow, while in the case of a Si/SiO₂ multilayer film,the band width ΔλIR of the infrared reflection region becomes wide.

As a result, in the case of a SiN/SiO₂ multilayer film (refractive indexdifference Δn=0.57), calculation with the reflection center wavelengthsλ0 of 780 nm and 950 nm shown in a reflection spectrum atlas of FIG. 8shows that the above-described conditions are substantially satisfiedwithin the range of 780 nm≦λ0≦950 nm. FIG. 8 shows the results ofcalculation of reflectance R so as to obtain the reflection centerwavelengths λ0 of 780 nm and 950 nm only by changing the thickness dj ofeach dielectric layer 1_j in the stacked structure shown in FIG. 13,which will be described below.

Similarly, in the case of a Si/SiO₂ multilayer film (refractive indexdifference Δn=2.64), a reflection spectrum atlas of FIG. 9 shows thatthe above-described conditions are substantially satisfied within therange of 900 nm≦λ0≦1100 nm.

Consequently, in a combination of silicon nitride SiN, silicon Si, andsilicon oxide SiO₂, the reflection center wavelength λ0 preferablysatisfies equation (3-1) below, and more preferably equation (3-2). Thismeans that the reflection center wavelength λ0 ideally near 900 nm.

Equation 3780 nm≦λ0≦1100 nm  (3-1)850 nm≦λ0≦1000 nm  (3-2)

Of course, the above-described materials are only examples, and theabove-described effects may be achieved by a material combination otherthan the combination of silicon oxide SiO₂ and silicon nitride SiNlayers. It is estimated from calculation that the same effects areobtained by selecting materials so that the refractive index differenceis 0.3 or more and more preferably 0.5 or more.

For example, the composition of an SiN film may slightly vary dependingon formation conditions. Examples of materials other than silicon oxideSiO₂ and silicon nitride SiN usable for the dielectric layers 1_jconstituting the dielectric stacked film 1 include oxides, such asalumina Al₂O₃, zirconia ZrO₂ (refractive index 2.05), titanium oxideTiO₂ (refractive index 2.3 to 2.55), magnesium oxide MgO, and zinc oxideZnO (refractive index 2.1); polymer materials, such as polycarbonate PC(refractive index 1.58) and acrylic resin PMMA (refractive index 1.49);and semiconductor materials, such as silicon carbide SiC (refractiveindex 2.65) and germanium Ge (refractive index 4 to 5.5).

By using a polymer material, an optical filter having characteristics,which are absent from ordinary glass optical filters, may be formed.Namely, a plastic optical filter has a light weight and excellentdurability (high temperature, high humidity, and impact).

Alternatively, in order to effectively decrease the dark current, asingle crystal layer made of a material having a wide band gap may bebonded to a surface of a semiconductor layer (semiconductor substrate, asemiconductor epitaxial layer, a semiconductor substrate and asemiconductor epitaxial layer formed thereon, or the like) in which aphotoelectric transducer is formed, thereby forming a high potentialbarrier.

For example, when a cubic SiC layer is bonded to a surface of an n-typeSi layer in which a photodiode is formed, with a SiC band gap of 2.2 eV,the potential barrier becomes 1.5 eV as shown by a depth-directionpotential distribution in FIG. 56. In this case, the potential barrieris higher than those in the cases shown in FIGS. 60A and 60B, therebydecreasing the dark current.

According to the above-described Fermi-Dirac distribution function, thedark current is decreased by about 12 digits at room temperature.

When the dark current is decreased, noise is also decreased to increasethe S/N ratio. As a result, with a small quantity of incident light,even when a signal is amplified with an amplifier, noise becomesunnoticeable.

Conceivable examples of the wide-band gap material include variousmaterials.

For example, the band gap may be changed by changing the compositionratio of a mixed crystal system, such as a compound semiconductor.Examples of the mixed crystal system include an AlGaInP mixed crystal, aSiC mixed crystal, a ZnCdSc mixed crystal, and an AlGaInN mixed crystal.

When a silicon layer is used as a semiconductor layer in whichphotoelectric transducers are formed, a SiC system using an element thesame group VI is preferred in view of ease of production and the like.

However, silicon and SiC have a high absolute value of lattice mismatchtherebetween, and thus misfit dislocation easily takes place at ajunction interface. The lattice mismatch is defined by the followingequation (equation 11):

$\begin{matrix}{{\Delta\; a} = \frac{a_{SiC} - a_{Si}}{a_{Si}}} & {{Equation}\mspace{14mu} 11}\end{matrix}$

wherein a_(SiC) and a_(Si) are lattice constants of SiC and Si,respectively.

In order to prevent the occurrence of misfit dislocation, for example,the thickness of a SiC film may be deceased to about a criticalthickness or less. For example, it has been found from experiments thethickness of a SiC film is preferably decreased to 30 nm or less.

It has been also found that when the composition ratio of C in SiC ishigh, for example, Si:C is 1:1, the thickness is preferably furtherdecreased to 15 nm or less.

Furthermore, Ge may be added to SiC to form a SiGeC mixed crystal, fordecreasing the absolute value of lattice mismatch Δa.

Table 1 shows the lattice constants of Si, Ge, and C crystal structures.

TABLE 1 Crystal structure Lattice constant (Å) Si Diamond 5.43095 GeDiamond 5.64613 C Diamond 3.56683

Table 1 indicates that in a SiC system, the absolute value of latticemismatch Δa is increased because the lattice constant of C is smallerthan that of Si.

Therefore, by mixing Ge having a larger lattice constant than that of Siwith SiC, the absolute value of lattice mismatch Δa is decreased to someextent.

Even when a single crystal layer is formed using SiGeC, the thickness ofthe single crystal layer is preferably 30 nm or less and more preferably15 nm or less.

Since SiGe not containing C has a narrower band gap than that of Si, Cis preferably added when the SiGe system is used for a single crystallayer.

As described above, the crystallinity is increased by adding Ge to forman SiGeC mixed crystal. However, the crystallinity may be increased byanother method.

Namely, at least one strained super lattice layer having a thickness of15 nm or less may be inserted at the interface between a semiconductorlayer such as a Si layer or the like and a single crystal layer such asa SiGeC layer or the like. The strained super lattice layer relievesstrain and removes dislocation in the planar direction, therebyincreasing crystallinity. In this case, a thin film of a super latticemay be any one of films having lattice constants different from that ofSi. In other words, for example, when a plurality of SiGeC system layershaving different composition rations is formed on a Si substrate, thesame effect as described above may be obtained.

In order to obtain a thin film including a single crystal layer of oneof the above-described compounds, any general crystal growth method suchas a CVD (chemical vapor deposition) method, a MOCVD (metal-organic CVD)method, a plasma CVD method, a MBE (molecular beam epitaxy) method, alaser abrasion method, a sputtering method, or the like may be used.

Alternatively, a carbonaceous material such as carbon or the like may bedeposited on a silicon surface and then annealed to carbonize thesilicon surface, thereby forming a SiC layer on the surface.

As described above, when the single crystal layer having a wide band gapis excessively thick, misfit dislocation occurs between the singlecrystal layer and a semiconductor layer. Therefore, the thickness ispreferably several tens nm or less.

On the other hand, when the layer is excessively thin, a tunnel effectoccurs, and thus the layer does not sufficiently function as a barrier.Therefore, the thickness is preferably 2 nm or more and more preferably5 nm or more.

When the wide-band-gap layer is an amorphous layer or polycrystallinelayer, not a single crystal layer, a level is formed at the interfacebetween the layer and a semiconductor layer disposed thereunder, therebyundesirably failing to sufficiently decrease the dark current.

<<Spectral Image Sensor Using Dielectric Stacked Film: FirstEmbodiment>>

FIGS. 10 to 14 are drawings illustrating a spectral image sensor 11corresponding to single wavelength spectral separation using adielectric stacked film according to a fist embodiment. The firstembodiment uses a basic method for designing a spectral image sensorusing a dielectric stacked film. Herein description will be made of anexample of a design of the spectral image sensor 11 in which adielectric stacked film 1 for selectively reflecting infrared light IRis used for cutting infrared light IR and receiving visible light VL.

When the dielectric stacked film 1 described above with reference toFIGS. 4 to 6 is formed on a semiconductor device layer on which adetecting element such as a silicon (Si) photodetector or the like isformed, the semiconductor device layer having a refractive index higherthan that of each of the dielectric layers 1_j of the dielectric stackedlayer 1, the distance between the semiconductor device layer and thedielectric stacked film 1, i.e., the thickness dk of the kth dielectriclayer 1_k including a silicon oxide SiO₂ layer, is important.

This means that as shown in a structural drawing of FIG. 10, the totalreflected light LR_(total) changes with the interference effect withreflected light L4 from the surface of a silicon substrate 1_ω which isthe surface of the semiconductor device layer (photodetector or thelike) composed of, for example, silicon Si (refractive index 4.1).

FIG. 11 is a spectrum atlas illustrating the dependency of the totalreflected light LR_(total) on variations of the thickness dk of thedielectric layer 1_k including a silicon oxide SiO₂ layer. FIG. 11 showsthe results of calculation with changes in the thickness dk of thedielectric layer 1_k in the dielectric stacked film 1 having theseven-layer structure shown in FIG. 4. In each spectrum of FIG. 11, thewavelength (μm) is shown as abscissa, and reflectance R is shown asordinate.

The spectra of FIG. 11 indicate that when the thickness dk is 0.154 μm,i.e., when the thickness satisfies conditional equation (1) for thereflection center wavelength λ0 of infrared light IR, the reflectionspectrum is little affected, and infrared light IR (wavelength λ≧780 nm)is strongly reflected. In contrast, when the thickness dk is 0.3 to 50μm, other vibrations occur in comparison to the refection spectrum withthe thickness dk=∞. It is thus found that there is a wavelength regionin which reflection of infrared light is decreased in a dip form.

However, when the thickness dk is 2.5 μm or more, the half-width of eachdip in infrared reflection is 30 nm or less, and particularly when thethickness dk is 5.0 μm or more, the half-width is 20 nm or less. As aresult, a half-width of general broad natural light is sufficientlydecreased to produce averaged reflectance. Furthermore, the spectra withthe thickness dk of 0.3 to 1.0 μm show that reflectance of visible lightVL is high. It is said from these results that the optimum thickness dkis preferably near 0.154 μm, i.e., a value satisfying conditionalequation (1).

FIG. 12 is a spectrum atlas illustrating the dependency on variations inthe thickness dk of the dielectric layer 1_k including a silicon oxideSiO₂ layer. In particular, FIG. 12 shows the results with changes of thethickness dk within a range near the thickness dk of 0.154 μm. In eachspectrum of FIG. 12, the wavelength (μm) is shown as abscissa, andreflectance R is shown as ordinate.

The results indicate that within a range of the thickness dk of 0.14 to0.16 μm with the thickness dk of 0.154 μm as a center which satisfiesconditional equation (1), reflection of visible light VL is suppressed.

Therefore, the optimum structure of the spectral image sensor 11substantially includes a dielectric staked film 1A having eight layersincluding the kth dielectric layer 1_k, as shown by a structural drawingof FIG. 13. FIG. 14 is a spectrum atlas showing the calculation resultsof the reflection spectrum of the dielectric stacked film 1A. In otherwords, the dielectric stacked film 1A provided on a silicon substrate1_ω has a structure including silicon oxide SiO₂ layers which are secondmaterial layers and provided in four cycles.

<<Spectral Image Sensor Using Dielectric Stacked Film: SecondEmbodiment>>

FIGS. 15 to 18 are drawings illustrating a spectral image sensorcorresponding to single wavelength spectral separation using adielectric stacked film 1 according to a second embodiment. The secondembodiment uses a first modified example of the designing method of thefirst embodiment. On the basis of the method described above withreference to FIGS. 10 to 14, modification is made so as to decreasereflection in the visible light region.

In the first modified example, a third material layer is insertedbetween the kth dielectric layer 1_k and a silicon substrate 1_ω, thethird material layer having an intermediate refractive index between therefractive index nk of the kth dielectric layer 1_k and the refractiveindex nω (=4.1) of the silicon substrate 1_ω.

Also, in accordance with the modification, in designing the constants ofthe first to seventh layers of the dielectric stacked film 1, thereflection center wavelength λ0 of infrared light IR is changed from 900nm to a lower wavelength, for example, 852 nm, the thickness dα (=d1,d3, . . . ; j=odd number) of silicon nitride SiN is 105 nm, and thethickness dβ (=d2, d4, . . . ; j=even number) of silicon oxide Sio₂ is146 nm. This is because a thin SiN layer (30 nm) is newly inserted todecrease the reflectance of visible light, and, at the same time,decrease the reflectance near the boundary at 780 nm between visiblelight and infrared light. Therefore, the entirety is shifted to a lowerwavelength side to compensate for these decreases in reflectance, andthe cut efficiency of infrared light near the boundary is improved. Ofcourse, the reflection center wavelength λ0 of infrared light IR may bekept at 900 nm.

Specifically, in the structure of the first modified example shown inFIG. 15, a silicon nitride SiN thin layer 1_γ having a relatively smallthickness dγ is inserted as the third layer material between the kthlayer of silicon oxide SiO₂ and the silicon substrate 1_ω. In thisexample, the thickness dγ is 0.030 μm. FIG. 16 shows the results ofcalculation of the reflection spectrum.

In the first modified example, the third layer material incorporated isthe same as the first layer material, silicon nitride SiN. However, anyother member having a higher refractive index than that of the siliconsubstrate 1_ω may be used.

The spectral image sensor 11 having the dielectric stacked film 1 of thefirst modified example substantially includes a dielectric stacked film1B having a nine-layer structure including the seven layers of thedielectric stacked film 1, the kth dielectric layer 1_k (silicon oxideSiO₂ layer), and the silicon nitride SiN layer 1_γ as a whole.

Furthermore, in the structure of a second modified example shown in FIG.17, a fourth layer material having a lower refractive index than that ofthe third layer material is inserted between the third layer materialinserted in the first modified example and the silicon substrate 1_ω.Specifically, a silicon oxide SiO₂ layer 1_δ is inserted as the fourthlayer material between the silicon nitride SiN layer 1_γ as the thirdlayer material having the thickness dγ and the silicon substrate 1_ω.The thickness dδ of the fourth layer material is 0.010 μm. FIG. 18 showsthe result of calculation of the reflection spectrum.

In the second modified example, the fourth layer material incorporatedis the same as the second layer material, silicon oxide SiO₂. However,any other member having a lower refractive index than that of the thirdlayer material (in this example, silicon nitride SiN) may be used.

The spectral image sensor 11 having the dielectric stacked film 1 of thesecond modified example substantially includes a dielectric stacked film1C having a ten-layer structure including the seven layers of thedielectric stacked film 1, the kth dielectric layer 1_k (silicon oxideSiO₂ layer), the silicon nitride SiN layer 1_γ, and the silicon oxideSiO₂ layer 1_δ as a whole. In other words, the dielectric stacked film1C has a structure in which the second layer material, silicon oxideSio₂, is provided in five cycles on the silicon substrate 1_ω.

The first and second examples are different in the presence of thesilicon oxide SiO₂ layer 1_δ, but FIGS. 16 and 18 indicate that in bothexamples, the reflectance of visible light VL is sufficiently decreased.Also, as in the second example, the effect of decreasing the darkcurrent by adding the silicon oxide SiO₂ layer 1_δ is obtained. Therelation between the thicknesses of both layers is preferably dδ<<dγ soas not to decrease the effect of addition of the silicon nitride SiNlayer 1_γ due to the addition of the silicon oxide SiO₂ layer 1_δ.

In this way, when the silicon nitride SiN thin layer 1_γ is added as anintermediate layer between the kth silicon oxide SiO₂ layer and thesilicon substrate 1_ω, the intermediate layer including a member havingan intermediate refractive index nγ (=nSiN) between the refractive indexnk (=nSiO₂) and the reflective index nω (=nSi), reflection of visiblelight VL may be suppressed. This is understood by the following thought.

First, assuming that the wavelength of visible light VL is λVL, theintermediate refractive index is Nm, and the thickness of theintermediate layer is dm, conditional equation (4) is obtained from thesame theory of a low-reflection film as equation (1). When equation (4)is satisfied, a satisfactory effect is exhibited.

Equation 4dm=λVL/(4×Nm)  (4)

wherein wavelength λVL indicates the whole of visible light VL, and thusthe wavelength region is given by the following equation (5):

Equation 5380 nm≦λVL≦780 nm  (5)

In each of the first and second examples, the silicon nitride SiN layer1_γ is added as an intermediate layer and has a reflective index nγ(=nSiN=Nm). Therefore, equation (5) indicating the wavelength region ischanged to equation (6) indicating the thickness dm of the intermediatelayer, i.e., the thickness dγ of the silicon nitride SiN layer 1_γ.

Equation 647 nm≦dm≦96 nm  (6)47 nm≦dγ≦96 nm  (6)

Although the thickness dm of the intermediate layer is ideally satisfiesequation (6), the thickness dm may slightly deviate therefrom. Accordingto experiments, a smaller thickness dm has an allowance. FIGS. 16 and 18confirm that for example, when the thickness dm is 30 nm, an effect isexhibited. Of course, since the intermediate layer (third layermaterial) is inserted between the kth layer of silicon oxide SiO₂ andthe silicon substrate 1_ω, the lower limit of the thickness of theintermediate layer is larger than 0 nm (excluding 0 nm). Namely, whenthe intermediate layer is inserted between the kth layer of siliconoxide SiO₂ and the silicon substrate 1_ω, the thicknesses dm and dγ ofthe intermediate layers preferably satisfy equation (7).

Equation (7)0 nm≦dm≦96 nm  (7)0 nm≦dγ<96 nm  (7)

<<Spectral Image Sensor Using Dielectric Stacked Film; ThirdEmbodiment>>

FIGS. 19 to 24 are drawings illustrating a spectral filter 10 and aspectral image sensor 11 corresponding to single wavelength spectralseparation using a dielectric stacked film 1 according to a thirdembodiment. FIGS. 19 to 22 are drawings illustrating the dielectricstacked film 1 constituting the spectral filter 10 according to thethird embodiment, and FIGS. 23 and 24 are drawings illustrating thespectral image sensor corresponding to single wavelength spectralseparation using the dielectric stacked film 1 according to the thirdembodiment.

In the third embodiment, the second modified example of the designmethod of the first embodiment is used, and the number of dielectriclayers 1_j of the dielectric stacked layer 1 is decreased. In order todecrease the number of the dielectric layers, a member (layer material)having a higher refractive index than those of the first and secondbasic layer materials which constitute the dielectric stacked film 1 isadded.

In order to add the member having a higher refractive index, one of thetwo basic layer materials, which has a higher refractive index, may bereplaced by a fifth layer material having a more higher refractiveindex. The dielectric stacked film 1 of the second modified examplebecomes a dielectric stacked film 1D substantially including a fifthlayer material 1_η. In other words, the dielectric stacked film 1D has astructure in which the second layer material, silicon oxide SiO2, isprovided in N cycles on the silicon substrate 1_ω.

With respect to the thickness dη of the fifth layer material, on theassumption that the refractive index of the fifth layer materials is nη,equation (8) is obtained from the same theory of a low-reflection filmas equation (1). When equation (8) is satisfied, a satisfactory effectis exhibited.

Equation (8)dη=λ0/(4nη)  (8)

For example, in an example shown by a structural diagram of FIG. 19, asilicon Si layer having a thickness dη of 61 nm and a refractive indexof 4.1 higher than those of silicon nitride SiN and silicon oxide SiO₂is added as the fifth layer material in place of one layer of siliconnitride SiN (the third dielectric layer 1_3). The results of calculationof the reflection spectrum are as shown in FIG. 20.

FIG. 20 shows the results of calculation with changes in the totalnumber of layers when a silicon nitride SiN layer at the center of thedielectric stacked film 1 having an odd total number of layers isreplaced by a silicon Si layer.

In FIG. 19, in designing the constants of the respective layers of thedielectric stacked film 1, the reflection center wavelength λ0 ofinfrared light IR is changed from 900 nm to 1000 nm, the thickness dα(=d1, d3, . . . ; j=odd number) of silicon nitride SiN is 123 nm, andthe thickness dβ (=d2, d4, . . . ; j=even number) of silicon oxide SiO₂is 171 nm.

In an example shown in a structural drawing of FIG. 21, in designing theconstants of the respective layers of the dielectric stacked film 1, thereflection center wavelength λ0 of infrared light IR is 900 nm, thethickness dα (=d1, d3, . . . ; j=odd number) of silicon nitride SiN is111 nm, and the thickness dβ (=d2, d4, . . . ; j=even number) of siliconoxide SiO₂ is 154 nm. Also, the silicon Si layer having a thickness dηof 55 nm is added as the fifth layer material in place of one layer ofsilicon nitride SiN. The results of calculation of the reflectionspectrum are as shown in FIG. 22.

The fifth layer material added to the second modified example is thesame as the silicon substrate 1_ω constituting the semiconductor elementlayer. However, any other member having a higher refractive index thanthose of the other dielectric layers 1_j constituting the dielectricstacked film 1.

The calculation results of the reflection spectra shown in FIGS. 20 and22 indicate that even with a small number of dielectric layers,sufficient reflectance is obtained by adding a layer material having ahigher refractive index than those of the dielectric layers 1_j otherthan the fifth layer material in the dielectric stacked film 1. Inparticular, a five-layer structure is optimum for separating betweenvisible light VL and infrared light IR because of the wide band width ofvisible light VL.

As described above in the first embodiment with reference to FIGS. 10 to12, in order to form the dielectric stacked film 1D on the semiconductorelement layer (silicon substrate 1_ω, the distance between thesemiconductor element layer and the dielectric stacked film 1D, i.e.,the thickness dk of the kth dielectric layer 1_k of silicon oxide SiO₂,is important.

This means that the total reflected light LR_(total) changes with theinterference effect with reflected light LR from the surface of thesilicon substrate 1_ω which is the surface of the semiconductor elementlayer (photodetector or the like) composed of, for example, silicon Si(refractive index 4.1), as shown in a structural diagram of FIG. 23.

FIG. 24 is a reflection spectrum atlas illustrating the dependency ofthe total reflected light LR_(total) on variations of the thickness dkof the dielectric layer 1_k of silicon oxide SiO₂ in the dielectricstacked film 1D having the five layer structure shown in FIG. 21. Ineach spectrum of FIG. 24, the wavelength λ (μm) is shown as abscissa,and reflectance R is shown as ordinate.

The spectrum of FIG. 24 indicate that when the thickness dk is 0.15 μm,i.e., when the thickness dk is near 0.154 μm satisfying conditionalequation (1) for the reflection center wavelength λ0 of infrared lightIR, the reflection spectrum is little affected, and infrared light IR(wavelength λ≧780 nm) is strongly reflected. In contrast, when thethickness dk is 0.3 to 50 μm, other vibrations occur in comparison tothe refection spectrum with the thickness dk=∞. It is thus found thatthere is a wavelength region in which reflection of infrared light isdecreased in a dip form. This is the same as described above in thefirst embodiment with reference to FIGS. 11 and 12.

<<Spectral Image Sensor Using Dielectric Stacked Film; FourthEmbodiment>>

FIGS. 25 and 26 are drawings illustrating a spectral image sensor 11corresponding to single wavelength spectral separation using adielectric stacked film 1 according to a fourth embodiment.

The fourth embodiment is a modified example of the third embodiment inwhich the number of the dielectric layers 1_j constituting thedielectric stacked film 1 is decreased. In the fourth embodiment, thenumber of the layers is further decreased. Specifically, in order todecrease the number of the layers, a plurality of members (layermaterials) having higher refractive indexes than those of the first andsecond basic layer materials constituting the dielectric stacked film 1is added. When a plurality of members having higher refractive indexesis added, one of the two basic layer materials, which as a higherrefractive index, may be replaced by a fifth layer material having ahigher refractive index. The dielectric stacked film 1 of this modifiedexample is a dielectric stacked film 1E having a structure substantiallyincluding a plurality of fifth layer materials 1_η.

Like in the third embodiment, as the plurality of fifth layer materials1_η, any members having higher refractive indexes than those of theother dielectric layers 1_j constituting the dielectric stacked film 1serving as a base may be used. The plurality of fifth layer materialsmay be the same or different.

With respect to the thickness dηp of the fifth layer materials, on theassumption that the refractive index of the fifth layer materials isnηp, equation (9) is obtained from the same theory of a low-reflectionfilm as equation (1). When equation (9) is satisfied, a satisfactoryeffect is exhibited.

Equation (9)dηp=λ0/(4nηp)  (9)

For example, in the example shown in a structural drawing of FIG. 25,the dielectric stacked film 1E having a three-layer structure is formed,two silicon Si layers each having a thickness dη of 61 nm and arefractive index of 4.1 hither than those of silicon nitride SiN andsilicon oxide SiO₂ are provided as the fifth layer material in place ofsilicon nitride. The results of calculation of the reflection spectrumare as shown in FIG. 26. In other words, the dielectric stacked film 1Ehas a structure in which a silicon oxide SiO₂ layer used as the secondlayer material is provided in two cycles on the silicon substrate 1_ω).

In designing the constants of each of the layers of the dielectricstacked film 1, the reflection center wavelength λ0 of infrared light IRis 1000 nm, the thickness of dη (=d1 and d3) of a silicon Si layer ofthe fifth layer material is 61 nm, and the thicknesses dβ (=d2) and dkof the two silicon oxide SiO₂ layers are 171 nm.

<<Spectral Image Sensor Using Dielectric Stacked Film; FifthEmbodiment>>

FIGS. 27 and 28 are drawings illustrating a spectral image sensorcorresponding to single wavelength spectral 11 separation using adielectric stacked film 1 according to a fifth embodiment.

Like in the second embodiment, in the fifth embodiment, the spectralimage sensor 11 of the third or fourth embodiment is modified todecrease the reflection in the visible light region.

In the example shown in a structural drawing of FIG. 27, a third layermaterial is inserted between the kth dielectric layer 1_k and thesilicon substrate 1_ω in the dielectric stacked film 1E of the fourthembodiment shown in FIG. 25, the third layer material having anintermediate refractive index between the refractive index nk of the kthdielectric layer 1_k and the refractive index nω (=4.1) of the siliconsubstrate 1_ω. Unlike in the second embodiment, in this embodiment, thereflection center wavelength λ0 of infrared light IR is kept at 1000 nm.Of course, like in the second embodiment, the reflection centerwavelength λ0 of infrared light IR may be changed to a lower side, not1000 nm.

Specifically, like in the first modified example in the secondembodiment, in the structure shown in FIG. 27, a silicon nitride SiNlayer 1_ν having a relatively small thickness dν is deposited as a thirdlayer material between the kth layer of silicon oxide SiO₂ and thesilicon substrate 1_ω. The thickness dν is 0.030 μm. The results ofcalculation of the reflection spectrum are as shown in FIG. 28. Thedielectric stacked film 1 in the spectral image sensor 11 of themodified example is a dielectric stacked film 1F having a five-layerstructure substantially including the three layers of the dielectricstacked film 1, the kth dielectric layer 1_k (silicon oxide SiO2 layer),and the silicon nitride SiN layer 1_ν as a whole.

The third layer material added in this modified example, is the same asthe first layer material, silicon nitride SiN. However, any other memberhaving a higher refractive index than that of the silicon substrate 1_ωmay be used.

Although not shown in the drawings, like in the second modified examplein the second embodiment, a fourth layer material having a lowerrefractive index than that of the third layer material may be insertedbetween the silicon substrate 1_ω and the third layer material insertedin this modified example.

In any cases, like in the second embodiment, reflectance in the visiblelight VL region may be decreased. In particular, the reflectances of ablue B component (wavelength near 420 nm) and a green G component(wavelength near 520 nm) are slightly increased, but the reflectance ofa red R component (wavelength near 600 nm) is sufficiently decreased.Therefore, this example is suitable for separation from infrared lightIR.

<Imaging Device Using Spectral Image Sensor: Corresponding to CCD>

FIGS. 29A, 29B, and 30 are drawings of circuits in the application ofthe spectral image sensor 11 of any one of the above-describedembodiments to an imaging device using an interline transfer-type CCDsolid-state imaging device (IT_CCD image sensor). An imaging device 100is an example of a physical information acquiring apparatus according toan embodiment of the invention.

In these drawings, reference numeral 11 denotes a spectral image sensor;reference numeral 12, a unit pixel matrix; reference numeral 100, animaging device; reference numeral 101, a CCD solid-state imaging device;reference numeral 122, a vertical transfer CCD; reference numeral 124, aread gate; reference numeral 126, a horizontal transfer CCD; referencenumeral 128, an output amplifier; reference numeral 140, an image signalprocessing part; reference numeral 142, an image switching control part;and reference numeral 146, a drive control part.

Like FIG. 3, FIGS. 29A and 29B show a structure for detecting infraredlight IR while separating a visible light VL band into R, G, and B colorcomponents, blue light B, green light G, and red light R, in whichvisible light VL and infrared light IR are independently detected. Theunit pixel matrix 12 has a structure substantially including pixels(photoelectric transducers) 12B, 12G, and 12R for respectivewavelengths, and a pixel 12IR not having the dielectric stacked film 1.

For example, as shown in FIG. 29A, the CCD solid-state imaging device101 includes a plurality of vertical transfer CCDs 122 provided in thevertical transfer direction in addition to the unit pixel matrix 12. Thecharge transfer direction of the vertical transfer CCDs 122, i.e., theread direction of image signals, coincides with the longitudinaldirection (the X direction in FIG. 29A).

Furthermore, MOS transistors serving as read gates 124 (124B, 124G,124R, and 124IR for respective wavelengths) are interposed between eachvertical transfer CCD 122 and each unit pixel matrix 12, and a channelstop (not shown) is provided at the boundary of each unit cell (unitcomponent).

As seen from FIG. 29A, one unit pixel matrix 12 has a structure forindependently detecting blue light B, green light G, red light R, andinfrared light IR, the structure substantially including the pixels 12B,12G, 12R, and 12IR for respective wavelengths (colors). In an imagingarea 110, a plurality of the vertical transfer CCDs 122 is provided forthe respective columns, for vertically transferring signal charges readfrom sensor parts 112 by the read gates 124, the sensor parts 112 eachincluding the unit pixel matrix 12.

In an arrangement of color filters 14, for example, the color filters 14are disposed in the order of blue, green, red, IR, blue, green, red, IR,. . . in the longitudinal direction (X direction) of the verticaltransfer CCDs 112 on the light-receiving surface of the siliconsubstrate 1_ω, and also in the order of blue, green, red, IR, blue,green, red, IR, . . . in the same direction (Y direction) with respectto the plurality of vertical transfer CCDs 122.

In each unit pixel matrix 12 (pixels 12B, 12G, 12R, and 12IR) of eachsensor part 112, when a drive pulse φROG corresponding to a read pulseROG is applied to the read gates 124, accumulated signal charges areread out to the vertical transfer CCDs 122 in the same vertical column.The transfer with the vertical transfer CCDs 122 is driven by a drivepulse φVx based on, for example, a 3- to 8-phase vertical transfer clockVx so that the read signal charges are sequentially transferred for eachportion corresponding to one scanning line (one line) in the verticaldirection in a portion of a horizontal blanking period. The verticaltransfer for each line is referred to as “line shift”.

Furthermore, in the CCD solid-state imaging device 101, horizontaltransfer CCDs 126 (horizontal register part or horizontal transfer part)arranged a line in a predetermined direction (for example, lateraldirection) is provided at the transfer ends of the plurality of verticaltransfer CCDs 122, i.e., adjacent to the vertical transfer CCDs 122 inthe last line. The transfer with the horizontal transfer CCDs 126 isdriven by drive pulses φH1 and φH2 based of, for example, 2-phasehorizontal transfer clocks H1 and H2 so that signal charges for one linetransferred from the plurality of vertical transfer CCDs 122 aresequentially horizontally transferred in a horizontal scanning periodafter the horizontal blanking period. Therefore, a plurality (two) ofhorizontal transfer electrodes corresponding to the two-phase transferis provided.

Furthermore, the output amplifier 128 having a charge-voltage conversionpart including a floating diffusion amplifier (FDA) is provided at thetransfer end of the horizontal transfer CCDs 126. The output amplifier128 is an example of physical information acquiring parts, in which thesignal charges horizontally transferred by the horizontal transfer CCDs126 are sequentially converted to voltage signals in the charge-voltageconversion part, amplified to a predetermined level, and then output.The voltage signals induce image signals as CCD outputs (V_(out))according to the quantity of incident light from an object. As a result,the interline transfer-type CCD solid-state imaging device 11 is formed.

The image signals induced as CCD outputs (V_(out)) from the outputamplifier 128 are input to the image signal processing part 140 shown inFIG. 29B. In the image signal processing part 140, an image switchingcontrol signal is input from the image switching control part 142 whichis an example of signal switching control parts. The CCD solid-stateimaging device 101 is driven by a drive pulse from the drive controlpart (an example of drive parts) 146.

The image switching control part 142 instructs to switch the output ofthe image signal processing part 140 to a visible VL monochrome or colorimage which is substantially not affected by infrared light IR, aninfrared IR image which is substantially not affected by visible lightVL, both images, or a mixed image of visible light VL and infrared lightIR, i.e., a pseudo-monochrome or pseudo-color image to which theluminance of infrared light IR is added. In other words, the imageswitching control part 142 controls simultaneous imaging output andswitched imaging output of a visible VL image and an infrared IR light.

This instruction may be given by external input for operating an imagingdevice or the image switching control part 142 may instruct to switchthe images by automatic processing using the visible light luminance notcontaining infrared light and output from the image signal processingpart 140.

The image signal processing part 140 performs, for example,synchronization for synchronizing image data R, G, B, or IR of eachpixel, stripe noise correction for correcting stripe noise produced by asmear phenomenon and a blooming phenomenon, WB (White Balance) controlfor controlling WB, gamma correction for controlling a gradient, dynamicrange enhancement for enhancing the dynamic range using pixelinformation of two screens having different charge storage times, or YCsignal generation for generating luminance data (Y) and color data (C).As a result, a visible light VL band image (i.e., an ordinary image) isobtained on the basis of imaging data (pixel data of R, G, B, IR) of theprimary colors of red (R), green (G), and blue (B).

The image signal processing portion 140 also produces an infrared IRimage using pixel data of infrared light IR. For example, when a colorfilter 14C is not provided in the pixel 12IR in which the dielectricstacked film 1 is not formed so that not only infrared light IR but alsovisible light VL simultaneously contribute to signals, ahigh-sensitivity image is obtained using pixel data from the pixel 12IR.Alternatively, when a green filter 14G is provided as a color filter14C, a mixed image of infrared light IR and green visible light LG isobtained. However, an image of infrared light IR alone is obtained usinga difference from the green component obtained from pixels 12G. When ablack filter 14BK is provided as a color filer 14C, an image of infraredlight IR alone is obtained using pixel data from pixels IR.

Each of the images produced as described above is sent to a display part(not shown) and displayed as a visible image for the operator, storeddirectly in a storage device such as a hard disk device or the like, orsent as processed data to other functional parts.

FIG. 30 shows a structure for independently detecting visible light VL(blue light, green light, and red light) and infrared light IR. Althoughdetails are not described, the basic configuration is the same as shownin FIGS. 29A and 29B, one unit pixel matrix 12 (photodiode group)substantially includes a visible light VL pixel 12W and a pixel 12IR nothaving the dielectric stacked film 1. This structure is the same asshown in FIGS. 29A and 29B except that the arrangement of color filters14 is different.

In an arrangement of the color filters 14, for example, the colorfilters 14 are disposed in the order of visible light VL, infrared lightIR, visible light VL, infrared light IR, . . . in the longitudinaldirection (X direction) of the vertical transfer CCDs 122 on thelight-receiving surface of the silicon substrate 1_ω, and also in theorder of visible light VL, infrared light IR, visible light VL, infraredlight IR, . . . in the same direction (Y direction) with respect to theplurality of vertical transfer CCDs 122.

<Imaging Device Using Spectral Image Sensor; Corresponding to CMOS>

FIGS. 31A and 31B and 32 are drawings showing circuits in application ofthe spectral image sensor 11 above described in the embodiments to animaging device using a CMOS solid-state imaging device (CMOS imagesensor). An imaging device 100 is a physical information acquiringdevice according to an embodiment of the invention.

In the drawings, reference numeral 100 denotes an imaging device;reference numeral 201, a CMOS solid-state imaging device; referencenumeral 205, a pixel amplifier; reference numeral 207, a drive controlpart; reference numeral 219, a vertical signal line; and referencenumeral 226, a column processing part.

Like FIG. 3, FIGS. 31A and 31B show a structure for detecting infraredlight IR while separating a visible light VL band into respective colorcomponents of R, G, and B. The structure is adapted for independentlydetecting blue light B, green light G, and red light R of visible lightVL and infrared light IR, and one unit pixel matrix 12 substantiallyinclude pixels (photoelectric transducer) 12B, 12G, and 12R forrespective wavelengths and a pixel 12IR not having a dielectric stackedfilm 1.

FIG. 32 shows a structure for independently detecting visible light VL(blue light, green light, and red light) and infrared light IR, and oneunit pixel matrix 12 (photodiode group) substantially include a pixel(photoelectric transducer) 12W for visible light VL and a pixel 12IR nothaving a dielectric stacked film 1. This structure is basically the sameas shown in FIG. 31A except that the arrangement of color filters 14 isdifferent (the same as in FIG. 30).

When a spectral image sensor is applied to a CMOS, a cell amplifier isprovided for each of pixels (photoelectric transducer) 12B, 12G, 12R,and 12IR in the unit pixel matrix 12. In this case, therefore, thestructure shown in FIG. 31A or FIG. 32 is used, in which pixel signalsare amplified by each cell amplifier and then output through a noisecanceling circuit or the like.

For example, the CMOS solid-state imaging device 201 includes a pixelpart in which a plurality of pixels each including a light-receivingelement (an example of a charge generating part) which outputs a signalaccording to a quantity of incident light are arranged in lines andcolumns (i.e., in a tow-dimensional matrix). A signal output from eachpixel is a voltage signal, and the imaging device 201 is a typicalcolumn type in which a CDS (Correlated Double Sampling) processingfunctional part, a digital conversion part (ADC; Analog DigitalConverter), and the like are provided in parallel to the columndirection.

Specifically, as shown in FIG. 31A, the CMOS solid-state imaging device201 includes a pixel part (imaging part) in which a plurality of pixels12 are arranged in lines and columns, and a drive control part 207, acolumn processing part 226, and an output circuit 228 which are providedoutside the pixel part 210.

Also, if required, an AGC (Auto Gain Control) circuit having a singleamplifying function may be provided in the same semiconductor region asthe column processing part 226 in front or behind the column processingpart 226. When AGC is performed in front of the column processing part226, analogue amplification is performed, while when AGC is performedbehind the column processing part 226, digital amplification isperformed. Since simple amplification of n-bit digital data may degradethe gradient, data is rather preferably subjected to analogueamplification and then converted to digital data.

The drive control part 207 has a control circuit function tosequentially read signals of the pixel part 210. For example, the drivecontrol part 207 includes a horizontal scanning circuit (column scanningcircuit) 212 for controlling column addresses and column scans, avertical scanning circuit (line scanning circuit) 214 for controllingline addresses and line scans, and a communication/timing control part220 having the function as an interface with the outside and thefunction to generate an internal clock.

The horizontal scanning circuit 212 has the function as a read scanningpart for reading count values from the column processing part 226. Thecomponents of the drive control part 207 are integrally formed togetherwith the pixel part 210 in a semiconductor region of single crystalsilicon using a technique equivalent to a technique for manufacturing asemiconductor integrated circuit to form a solid-state imaging device(imaging device) as an example of semiconductor systems.

FIG. 31A shows only a portion of lines and columns for the sake ofsimplicity, but several tens to several thousands of pixels 12 arearranged in each line and each column. Each of the pixels 12 includesthe unit pixel matrix 12 serving as a light-receiving element (chargegenerating part) and pixel amplifiers (cell amplifiers; pixel signalgenerating part) 205 (205B, 205G, and 205R for respective colors) eachhaving an amplification semiconductor element (for example, transistor).

As seen from FIG. 31A, one unit pixel matrix 12 has a structure forindependently detecting blue light B, green light G, red light R, andinfrared light IR, and substantially includes pixels 12B, 12G, 12R, and12IR for respective wavelengths (colors).

In an arrangement of color filters 14, for example, the color filters 14are disposed in the order of blue, green, red, IR, blue, green, red, IR,. . . in the X direction on a light-receiving surface of a siliconsubstrate 1_ω, and also in the order of blue, green, red, IR, blue,green, red, IR, . . . in the Y direction perpendicular to the Xdirection.

As each pixel amplifier 205, a floating diffusion amplifier is used. Anexample of the pixel amplifiers 205 include four general-purposetransistors for a CMOS sensor, including a read selection transistor asan example of a charge read part (transfer gate part/read gate part)relative to a charge generation part, a reset transistor as an exampleof a reset gate part, a vertical selection transistor, and asource-follower amplification transistor as an example of a detectingelement for detecting a voltage change of floating diffusion.

As disclosed in U.S. Pat. No. 2,708,455, another type of amplifier maybe used, which includes the three transistors, i.e., an amplificationtransistor connected to a drain line (DRN), for amplifying a signalvoltage corresponding to a signal charge generated from the chargegeneration part, a reset transistor for resetting the pixel amplifier205, and a read selection transistor (transfer gate part) scanned by avertical shift resistor through transfer wiring (TRF).

The pixels 12 are connected to the vertical scanning circuit 214 throughline control lines 215 and to the column processing part 226 throughvertical signal lines 219. The line control lines 215 include the entirewiring extending from the vertical scanning circuit 214 to the pixels.For example, the line control lines 215 are arranged in parallel to along scatterer 3.

The horizontal scanning circuit 212 and the vertical scanning circuit214 each include, for example, a shift resistor and a decoder to startan address selection operation (scanning) in response to a controlsignal output from the communication/timing control part 220. Therefore,the line control lines 125 include various pulse signals (for example,reset pulse RST, transfer pulse TRF, DRN control pulse DRN, etc.) fordriving the pixels 12.

Although not shown in the drawing, the communication/timing control part220 includes a functional block functioning as a timing generator TG (anexample of read address control devices) for supplying a clock necessaryfor the operation of each part and a pulse signal with predeterminedtiming, and a functional block functioning as a communication interfacefor receiving a master clock CLKO through a terminal 220 a, receivingdata DATA for instructing an operation mode through a terminal 220 b,and outputting data including information of the CMOS solid-stateimaging device 201 through a terminal 220 c.

For example, a horizontal address signal and a vertical address signalare output to a horizontal decoder and a vertical decoder, respectively,and each decoder selects a corresponding line or column to drive thepixels 12 and the column processing part 226 through a drive circuit.

In this case, since the pixels are arranged in a two-dimensional matrix,analogue pixel signals generated from the pixel amplifiers (pixel signalgenerating part) 205 and output in the column direction through thevertical signal lines 219 are accessed by column units (parallel to thecolumn direction) and read by (vertical) scanning. Then, pixel signalsare accessed in the line direction vertical to the vertical direction toread pixel signals (for example, digital pixel data) to the output sideby (horizontal) scanning. Therefore, the read speeds of pixel signalsand pixel data are desirably increased. Of course, random access may becarried out, in which the address of the pixel 12 to be read is directlyspecified to read only the information of the necessary pixel 12.

The communication/timing control part 220 supplies clock CLKI at samefrequency as the master clock CLKO input through the terminal 220 a anda low-speed clock obtained by dividing the frequency into two or moreparts to each part of the device, for example, the horizontal scanningcircuit 212, the vertical scanning circuit 214, the column processingpart 226, and the like.

The vertical scanning circuit 214 selects a column of the pixel part 210and supplies a pulse necessary for the column. For example, the verticalscanning circuit 214 includes a vertical decoder for specifying(selecting a column of the pixel part 210) a read column in the verticaldirection, and a vertical drive circuit for supplying a pulse to theline control line 215 corresponding to the pixel 12 at the read address(column direction) specified by the vertical decoder to drive the pixel12. The vertical decoder selects a column for an electronic shutter aswell as a column for reading signals.

The horizontal scanning circuit 212 successively selects column circuits(not shown) in the column processing part 226 in synchronism withlow-speed clock CLK2 and leads the signal to horizontal signal lines(horizontal output lines) 218. For example, the horizontal scanningcircuit 212 includes a horizontal decoder for specifying (selecting eachcolumn circuit in the column processing part 226) a read column in thehorizontal direction and a horizontal drive circuit for leading eachsignal of the column processing part 226 to the horizontal signal lines218 using selection switches 227 according to the read address specifiedby the horizontal decoder. For example, when the number n (a positiveinter) of bits handled by a column AD circuit is 10 (=n), the number ofthe horizontal signal lines 218 is 10 corresponding to the number ofbits.

In the CMOS solid-state imaging device 201 having the above-describedconfiguration, the pixel signals output from the pixels 12 supplied, foreach vertical line, to the column circuits of the column processing part226 through the vertical signal lines 219. The signal charges stored inthe unit pixel matrix 12 (pixels 12B, 12G, 12R, and 12IR) are redthrough the same vertical signal line 219.

Each column circuit of the column processing part 226 receives signalsfrom the pixels in one column and processes the signals. For example,each column circuit has an ADC (Analog Digital Converter) circuit forconverting analogue signals to 10-bits digital data using, for example,the low-speed clock CLK2.

By using a proper circuit configuration, pixel signals input in avoltage mode through the vertical signal lines 219 may be processed soas to produce differences between the signal level (noise level)immediately after pixel reset and true (corresponding to the quantity ofincident light) signal level V_(sig). Consequently, noise signalcomponents such as fixed pattern noise (FPN) and reset noise may beremoved.

The analogue pixel signals (or digital pixel data) processed in thecolumn circuits are transmitted to the horizontal signal lines 218through the horizontal selection switches 217 driven by the horizontalselection signals output from the horizontal scanning circuit 212 andthen input to the output circuit 28. The number 10 of bits is anexample, and the number of bits may be less than 10 (for example, 8) ormay exceed 10 (for example 14).

In the above-described configuration, pixel signals are sequentiallyoutput from the pixels in each vertical line in the pixel part 210 inwhich the unit pixel matrixes 12 (pixels 12B, 12G, 12R, and 12IR)serving as the charge generating parts are arranged in a matrix.Therefore, one image corresponding to the pixel part 210 in which thelight-receiving devices are arranged in a matrix, i.e., a frame image,is displayed as a collection of the pixel signals of the entire pixelpart 210.

The output circuit 228 corresponds to the output amplifier 128 in theCCD solid-state imaging device 101, and like in the CCD solid-stateimaging device 101, the image signal processing part 140 is providedbehind the output circuit 228, as shown in FIG. 31B. Also, like in theCCD solid-state imaging device 101, an image switching control signal isinput to the image signal processing part 140 from then image switchingcontrol part 142.

As a result, an image of the visible light VL band (i.e., an ordinaryimage) is obtained on the basis of the imaging data (pixel data of R, G,B, and IR) of the primary colors of red (R), green (G), and blue (B) orpixel data for visible light VL, and infrared light IR image is alsoobtained using pixel data of infrared light IR.

Although not shown in the drawings, when the pixels 12IR are removedfrom the basic structure shown in FIG. 29 or 31A, the respective colorcomponents of R, G, and B in the visible light VL band are separatelydetected.

In an arrangement of color filters 14, for example, the color filters 14are disposed in the order of blue, green, red, green, blue, green, red,green, blue, . . . in the longitudinal direction (X direction) of thevertical transfer CCDs 122 on the light-receiving surface of the siliconsubstrate 1_ω, and also in the order of blue, green, red, green, blue,green, red, green, blue . . . in the same direction (Y direction) withrespect to the plurality of vertical transfer CCDs 122. Alternatively,in a 2×2 unit pixel matrix 12, two green (G) pixels and one pixel ofeach of red (R) and blue (B) colors are disposed in a so-called Bayerarrangement, or a fourth color (e.g., emerald) is added to the threecolors of B, G, and R in order to extend a range of color reproduction.

In such a case, only an image of the visible light VL band is obtained,but an infrared cut filter may not be disposed as an example ofsubtractive color filters in front of a sensor. Since an expensiveinfrared cut filter may not be disposed, the cost is significantlydecreased. Also, since a thick and heavy infrared cut filter may not bedisposed, an optical system may be made lightweight and compact. Ofcourse, an infrared cut filter insertion/extraction mechanism may not beprovided, and thus a device is not increased in scale.

This advantage in cost also applies to a structure in which an existinginfrared cut filter made of glass is replaced by a dielectric stackedfilm, and an imaging sensor and a dielectric stacked film are separatelyformed (a detecting part and a dielectric stacked film are separatelyformed).

For example, a device is advantageous in cost and made compact ascompared with use of an existing infrared cut filter made of glass, andthus an imaging device having excellent portability, such as a digitalcamera or the like, may be provided.

In a structure in which an infrared cut filter is disposed in front of asensor, a glass substrate is inserted in front of a CCD or CMOS imagingdevice to produce an air-glass interface in the course of an opticalpath. Therefore, visible light to be transmitted is reflected by theinterface, thereby causing the problem of decreasing sensitivity.Furthermore, the number of such interfaces is increased, and thus theangle of refraction in oblique incidence (within glass) varies withwavelength, thereby causing blooming due to a change in the opticalpath. In this case, use of a dielectric stacked film has the advantagethat the blooming according to wavelength is prevented.

<<Example of Manufacturing Process>>

FIGS. 33A to F are drawings illustrating an example of a process formanufacturing a spectral image sensor having any one of the sensorstructures described above in the embodiments. Namely, FIGS. 33A to Fare drawings illustrating an example of a process for manufacturing aspectral image sensor including a light receiving part for infraredlight IR and a light receiving part for visible light VL.

In forming this structure, as shown in FIG. 29, 30, or 31A and 32, ageneral CCD or CMOS-structure circuit is first formed (FIG. 33A). Then,a Sio₂ film and a SiN film are successively deposited on a Si photodiodeby, for example, CVD (Chemical Vapor Deposition) or the like (FIG. 33B).

Then, only one of four pixels is etched by a RIE (Reactive Ion Etching)method) or the like to form an opening in the light receiving part forinfrared light IR so that the opening reaches the SiO₂ film in thelowermost layer (FIG. 33E).

Next, in order to protect the dielectric stacked film 1 and the like, aSiO₂ film is again deposited on the dielectric stacked film 1 by, forexample, CVD, the dielectric stacked film 1 having the opening formed ina portion thereof (FIG. 33F). This process may be appropriately changed.

In this process, a photoresist having an opening corresponding to thelight-receiving part for infrared light IR may be used so as not to etchthe three pixels (R, G, and B components) of visible light VL (FIGS. 33Cand 33D). In this case, the photoresist is removed before the SiO₂ filmis deposited on the dielectric stacked film 1 (FIGS. 33D to E).

Although not shown in the drawings, a color filter and a micro lens maybe further formed on the SiO₂ film for each pixel.

Furthermore, when infrared light IR slightly leaks to enter aphotoelectric transducer (photodiode or the like) for visible light VL,an entirely weak ultraviolet cut filter may be disposed. For example,even when an infrared cut filter with a cut rate of 50% or less isdisposed to cut infrared light to a level which causes substantially noinfluence on visible light VL, infrared light IR is converged in aphotoelectric transducer (photodiode or the like) for infrared light IR,thereby causing sufficient sensitivity.

In this manufacturing process, etching is performed to a portion nearthe Si substrate, i.e., the opening reaching the SiO₂ film in thelowermost layer is formed in the light receiving part for infrared lightIR (FIG. 33E). Therefore, etching may cause the problem of damaging. Inthis case, the damaging may be decreased by increasing the thickness dof the SiO₂ film immediately above the Si substrate.

When dk is 2.5 μm or more, as shown in FIG. 11, the half width of a dipin the infrared IR region of a reflection spectrum narrows, and thus thereflectance is averaged for general natural broad light, therebypermitting reflection of infrared light. Therefore, the thickness dk ofthe kth dielectric layer 1_k is preferably 2.5 μm or more and morepreferably 5 μm or more.

When metal wiring for photodiodes and pixel amplifiers which are formedon the silicon substrate 1_ω, i.e., a wiring layer for forming signallines for reading pixel signals as unit signals from the pixelamplifiers serving as unit signal generating parts in an imaging part(detection region), is formed immediately above the silicon substrate1_ω, the dielectric stacked film 1 is formed at some distance from thesilicon substrate 1_ω as compared with a structure in which thedielectric stacked film 1 is formed immediately above the siliconsubstrate 1_ω. In other words, the dielectric stacked film 1 is formedabove the metal wiring, and thus the process is simplified, therebycausing the advantage of low cost. In detail, when the number of thelayers constituting the dielectric stacked film 1 is increased, a rathersatisfactory effect is obtained. Hereinafter, a metal wiring-consciousspectral image sensor will be described.

<<Spectral Image Sensor Using Dielectric Stacked Film; SixthEmbodiment>>

FIGS. 34 to 40 are drawings illustrating a spectral image sensor 11corresponding to single wavelength spectral separation using adielectric stacked film 1 according to a sixth embodiment. In the sixthembodiment, on the basis of the process described above with referenceto FIGS. 10 to 14, the dielectric stacked film 1 is formed integrallywith a detecting part such as a photodiode or the like above a siliconsubstrate 1_ω at some distance from the silicon substrate 1_ω in view ofmetal wiring.

For example, in a CMOS structure, as shown in FIG. 34, a wiring layer isformed above a semiconductor element layer in which detecting parts suchas photodiodes or the like are formed. When the thickness of the wiringlayer is about 0.7 μm, a multilayer structure may be integrally formedabout 0.7 μm above the silicon substrate 1_ω on which photodiodes arethe like are formed, and the dielectric stacked layer 1 may be formedafter the process for a first wiring layer. In this case, the wiringlayer is provided in the kth layer having a thickness dk of about 0.7μm.

Furthermore, as shown in FIG. 35, when three wiring layers having atotal thickness of about 3.2 μm are provided on a semiconductor elementlayer, a multilayer structure may be integrally formed about 3.2 μmabove a silicon substrate 1_ on which photodiodes and the like areformed, and a dielectric stacked film 1 may be formed after the processfor the third wiring layer at the top. In this case, the wiring layersmay be formed in the kth layer having a thickness dk of about 3.2 μm.

In this example, as shown in the drawing, the thickness of about 3.2 μmrepresents the thickness of the layer k excluding the thickness of about10 nm of a SiO₂ layer (δ layer) provided on the silicon substrate 1_ωand the thickness of about 65 nm of a SiN layer (γ layer) provided onthe layer.

Color filters 14 and microlenses may be formed after the dielectricstacked film 1 is formed.

As the spectral image sensor 11 corresponding this example, for example,as shown in FIG. 36, in the seven-layer structure of the secondembodiment shown in FIG. 17, a dielectric stacked film 1C including thethree layers including the kth dielectric stacked layer 1_k (siliconoxide SiO₂ layer), a silicon nitride SiN layer 1_γ, and a silicon oxideSiO₂ layer 1_δ is used as a base, the kth dielectric layer 1_k having athickness of 700 nm. In the dielectric stacked film 1C, the relativelythin silicon nitride SiN layer 1_γ has a thickness dγ of 65 nm or 100 nmand is deposited as a third layer material between the kth silicon oxideSiO₂ layer and the silicon substrate 1_ω, and the silicon oxide SiO₂layer 1_δ has a thickness dδ of 10 nm and a lower refractive index thanthat of the third layer material and is deposited as a fourth layermaterial between the third layer material and the silicon substrate 1_ω.

In FIG. 37, a basic dielectric stacked film 1 has a nine-layer structurein which the kth dielectric layer 1_k has a thickness of 700 nm or 3.2μm. In a dielectric stacked film 1C, a relatively thin silicon nitrideSiN layer l_γ having a thickness dγ of 65 nm is deposited as a thirdlayer material between the kth silicon oxide SiO₂ layer and the siliconsubstrate 1_ω, and a silicon oxide SiO₂ layer 1_δ has a thickness dδ of10 nm and a lower refractive index than that of the third layer materialis deposited as a fourth layer material between the third layer materialand the silicon substrate 1_ω.

The results of calculation of reflection spectra of these structures areas shown in FIGS. 38 to 40. As seen from FIGS. 37 and 36, the dielectricstacked film 1 is formed about 0.7 μm or 3.2 μm above the siliconsubstrate 1_ω, and thus the wiring process is simplified. Correctly, theSiO₂ layer as the fourth layer material and the SiN layer as the thirdlayer material having thicknesses of 10 nm and 65 nm (or 100 nm),respectively, are present in order immediately above the siliconsubstrate 1_ω, the dielectric stacked film 1 is more than 0.7 μm or 3.2μm above the silicon substrate 1_ω.

The seven-layer dielectric stacked film 1 and the nine-layer dielectricstacked film 1 each including SiN films and SiO₂ films are describedabove. However, as shown in FIG. 39, when the number of the layers isincreased from 7 to 9, the reflectance R in the infrared IR region issufficiently increased to 0.9 or more.

As shown in FIG. 40, in a seven-layer structure in which the thicknessdk of the kth dielectric layer 1_k is 3.2 μm, a dip in the infraredreflection region is large, resulting in a significant decrease inreflection. However, it is found that the dip is decreased by increasingthe number of layers to 9, reflection in the infrared IR region becomessufficient.

Also, FIG. 38 indicates that when the thickness dγ of the SiN layer asthe third layer material is large, reflection in the visible light VLregion is increased. This possibly due to the fact that as describedabove in the second embodiments, the third layer material is provided asan intermediate layer for decreasing reflection in the visible lightregion, and the thickness dγ of the dielectric layer 1_γ provided as anintermediate layer ideally satisfies equation (6). Namely, there is alarge allowance on the thin layer side, but there is a small allowanceon the thick layer side.

As described above, when the dielectric stacked film 1 is formed after ageneral wiring process, manufacture is simplified, and a new process maynot be added, thereby causing an advantage in cost. In other words, theprocess for manufacturing the CMOS structure shown in FIG. 35 issimplified to exhibit a good effect. When the wiring process isperformed after the dielectric stacked film 1 is formed, it may bedifficult to remove the dielectric stacked film 1.

Further embodiments of the invention will be described below.

FIG. 54 is a drawing (schematic plane view) showing a schematicconfiguration of a solid-state imaging device according to a seventhembodiment.

In this embodiment, a solid-state imaging device according to anembodiment is applied to a CCD solid-state imaging device.

In FIG. 54, reference numeral 1001 denotes a solid-state imaging device;reference numeral 1002, a CCD register; reference numeral 1003, ahorizontal CCD register; and reference numeral 1004, an outputamplifier.

In the solid-state imaging device 1001, photodiodes PD serving as lightreceiving parts are arranged in a matrix, and the vertical CCD registers1002 extending vertically (in the longitudinal direction in the drawing)are provided for the respective columns of the light receiving parts(photodiodes PD). Also, the horizontal CCD register 1003 extendinghorizontally (the lateral direction of the drawing) is connected to theends of the vertical CCD registers 1002. Furthermore, an output part1005 is connected to an end of the horizontal CCD register 1003 throughthe output amplifier 1004.

FIG. 55 is a sectional view of the solid-state imaging device 1001including the light receiving parts shown in FIG. 54.

In FIG. 55, reference numeral 1001 denotes the solid-state imagingdevice; reference numeral 1002, the vertical CCD register; referencenumeral 1011, a silicon substrate; reference numeral 1012, a p-typesemiconductor well region; reference numeral 1013, a (n-type) chargestorage region; reference numeral 1015, a transfer channel region;reference numeral 1019, a transfer electrode; reference numeral 1021, alight-shielding film; and reference numeral 1025, a single crystallayer. PD represents a photodiode.

As shown in FIG. 55, the p-type semiconductor well region 1012 is formedon the n-type silicon substrate 1011, and a semiconductor region inwhich the photodiodes PD and the vertical CCD registers 1002 are formedis formed in the p-type semiconductor well region 1012.

Each photodiode PD serves as a photoelectric transducer and includes then-type charge storage region 1013 formed in an upper portion of thep-type semiconductor well region 1012, these regions 1012 and 1013constituting each photodiode.

In each vertical CCD register 1002, the n-type transfer channel region1015 to which signal charges are transferred is formed near the surfaceof the p-type semiconductor well region 1012, and a second p-typesemiconductor well region 1014 is formed below the n-type transferchannel region 1015.

Also, a p-type channel stop region 1016 is formed between the n-typecharge storage region 1013 of each photodiode PD and the right n-typetransfer channel region 1015, for preventing signal charges from flowinginto the right n-type transfer channel region 1015 from the n-typecharge storage region 1013.

Furthermore, a read gate region 1017 is formed between the n-type chargestorage region 1013 of each photodiode PD and the left n-type channelregion 1015.

Furthermore, the transfer electrode 1019 composed of polycrystallinesilicon is formed on the silicon substrate 1011 with a gate insulatingfilm 1018 provided therebetween. The transfer electrode 1019 is formedover the read gate region 1017, the transfer channel region 1015, andthe channel stop region 1016, and the transfer electrode 1019 has anopening formed above the charge storage region 1013 of each photodiodePD.

In the solid-state imaging device according to this embodiment, thesingle crystal layer 1025 composed of a material, for example, SiC orSiGeC, which has a wider band gap than that of silicon of the siliconsubstrate 1011, is bonded to the top of the silicon substrate 1011 onwhich the photodiodes (photoelectric transducers) of the light receivingparts are formed.

By providing the single crystal layer 1025, the dark current issignificantly decreased, as compared with a general configuration.

As described above, when SiC or SiGeC is used for the single crystallayer 1025, the thickness of the single crystal layer 1025 is preferably30 nm or less, for example, about 10 nm.

The single crystal layer 1025 may be formed by any one of theabove-described methods such as CVD and the like.

In the solid-state imaging device 1001 according to this embodiment, thesingle crystal layer 1025 composed of a material having a wider band gapthan that of silicon of the silicon substrate 1011 is bonded to thesilicon substrate 1011 on which the photodiodes PD are formed. Since thesingle crystal layer 1025 has a wider band gap, the barrier againstelectrons at the surface level is increased to decrease the dark currentdue to the electrons. For example, the dark current may be significantlydecreased by 12 digits, and thus the S/N ratio of signals for incidentlight may be significantly increased.

As a result, even when the signal gain is increased for increasingsensitivity under imaging conditions such as a small quantity ofincident light in a dark room or the like, an image without significantnoise may be obtained.

Also, even when the solid-state imaging device 1001 has low sensitivity,a high-quality image may be obtained only by amplification with anamplifier regardless of the quantity of incident light.

Furthermore, even when the pixels of the solid-state imaging device 1001made fine to decrease the quantity of incident light, a sufficient S/Nratio may be secured, and thus an image without significant noise may beobtained only by amplification with an amplifier for compensating forlow sensitivity.

Therefore, by making the pixels in the solid-state imaging device 1001fine, the number of pixels in the solid-state imaging device 1001 may beincreased, and the solid-state imaging device may be decreased in size.

EXAMPLES

A solid-state imaging device 1001 according to this embodiment wasactually formed and examined with respect to characteristics.

First, a solid-state imaging device 1001 including a SiC layer formed asa single crystal layer 1025 was formed.

The SiC layer was grown to a thickness of about 10 nm on a siliconsubstrate 1011 by, for example, a CVD method to form the single crystallayer 1025. In this step, for example, C₃H₈ and monosilane SiH₄ wereused as raw materials, and the substrate temperature was 1100° C. orless.

The SiC layer may be formed by a method other than the CVD method. Forexample, the SiC layer may be grown by a laser abrasion method using SiCas a target material.

Next, the solid-state imaging device 1001 shown in FIGS. 54 and 55 wasmanufactured by a usual process for manufacturing a CCD solid-stateimaging device.

In actual imaging with the solid-state imaging device 1001 manufactured,the dark current was significantly decreased, and an image withoutsignificant noise was obtained even by imaging under dark conditions.

Next, a solid-state imaging device 1001 including a SiGeC layer formedas a single crystal layer 1025 was formed.

First, a silicon substrate 1011 was dipped in a mixed solution of NH₄OH,H₂O₂, and H₂O (mixing ratio of 1:1:5) for 10 minutes to wash thesurface.

Then, the substrate was treated with HF (HF:H₂O=1:50) for 10 seconds toremove a native oxide film from the surface of the silicon substrate1101.

In these steps, the surface of the silicon substrate 1011 was cleaned,for improving the crystallinity of subsequent crystal growth.

The silicon substrate 1011 from which the native oxide film was removedby the above-described pre-treatment was mounted on a substrate holder.

Next, the SiGeC layer was deposited as the single crystal layer 1025 onthe silicon substrate 1011 by low-pressure CVD.

First, propane C₃H₈ was supplied at 450 μmol/min at a pressure of 1×10⁴Pa, a substrate temperature of 1150° C., and a hydrogen gas flow rate of1 l/min, and this state was maintained for 2 minutes to carbonize thesurface of the silicon substrate 1011.

Furthermore, monosilane SiH₄, C₃H₈, and GeH₄ were simultaneouslysupplied at 36 μmol/min, 59 μmol/min, and 10 μmol/min, respectively, togrown a SiGeC crystal on the silicon substrate for 30 seconds bylow-pressure CVD. As a result, the SiGeC crystal as the single crystallayer 1025 was deposited to a thickness of about 10 nm.

Although, in this example, low-pressure CVD was used, the SiGeC layermay be formed by another method. For example, the crystal may be grownby a laser abrasion method using SiGeC as a target material or by a gassource MBE method using an organometallic material such as anorganosilane material or the like.

Next, the solid-state imaging device 1001 shown in FIGS. 54 and 55 wasmanufactured by a usual process for manufacturing a CCD solid-stateimaging device.

In actual imaging with the solid-state imaging device 1001 manufactured,the dark current was significantly decreased, and an image withoutsignificant noise was obtained even by imaging under dark conditions.

In the above embodiment, the single crystal layer 1025 is formed overthe entire region of the silicon substrate 1011. However, the singlecrystal layer may be partially etched off by RIE (reactive ion etching)or the like excluding portions corresponding to the photodiodes PD, forimproving electric characteristics. In this case, the photodiodes may beprotected with a mask by photolithography before etching.

An embodiment relating to this case will be described below.

FIG. 57 is a drawing (sectional view) showing a schematic configurationof a solid-state imaging device according to another embodiment of theinvention.

In FIG. 57, reference numeral 1030 denotes a solid-state imaging device;reference numeral 1002, a vertical CCD register; reference numeral 1011,a silicon substrate; reference numeral 1012, a p-type semiconductor wellregion; reference numeral 1013, a (n-type) charge storage region;reference numeral 1015, a transfer channel region; reference numeral1019, a transfer electrode; reference numeral 1021, a light-shieldingfilm; reference numeral 1026, a single crystal layer; and referencenumeral 1051, a cell amplifier. PD represents a photodiode.

In the solid-state imaging device 1030 according to this embodiment, thesingle crystal layer 1026, for example, composed of SiC or SiGeC, isformed the surfaces of only the photodiodes PD of the silicon substrate1011. The single crystal layer 1026 is boded to the silicon substrate1011.

The other portions are the same as in the solid-state imaging device1001 of the above-described embodiment, and are denoted by the samereference numerals and not described below.

The single crystal layer 1026 may be formed by depositing a film for thesingle crystal layer 1026 over the entire region, and then partiallyremoving the film by etching such as RIE (reactive ion etching) to leaveportions corresponding to the photodiodes PD.

In the configuration of the solid-state imaging device 1030 of thisembodiment, the single crystal layer 1026 having a wider band gap thanthat of silicon of the silicon substrate 1011 is provided to be bondedto the photodiodes PD on the silicon substrate 1011. Since the singlecrystal layer 1026 has a wider band gap, the barrier against electronsat the surface level is increased to decrease the dark current due tothe electrons. Furthermore, the dark current may be significantlydecreased by 12 digits to significantly improve the S/N ratio of signalsof incident light.

Therefore, even when the signal gain is increased for increasingsensitivity under imaging conditions such as a small quantity ofincident light in a dark room or the like, an image without significantnoise may be obtained.

Also, even when the solid-state imaging device 1030 has low sensitivity,a high-quality image may be obtained only by amplification with anamplifier regardless of the quantity of incident light.

Furthermore, even when the pixels of the solid-state imaging device 1030is made fine to decrease the quantity of incident light, a sufficientS/N ratio may be secured, and thus an image without significant noisemay be obtained only by amplification with an amplifier for compensatingfor low sensitivity.

Therefore, by making the pixels in the solid-state imaging device 1030fine, the number of pixels in the solid-state imaging device 1030 may beincreased, and the solid-state imaging device may be decreased in size.

A solid-state imaging device 1030 according to the embodiment shown inFIG. 57 was actually formed and examined with respect tocharacteristics.

Pre-treatment and deposition of a SiGeC layer were performed asdescribed above to form a SiGeC layer as a single crystal layer 1026 ona silicon substrate 1011.

Next, SiGeC layer was partially removed by lithography and RIE techniqueto leave portions corresponding to photodiodes PD, thereby forming thesingle crystal layer 1026 composed of SiGeC only on the photodiodes PD.

Next, the solid-state imaging device 1030 shown in FIG. 57 wasmanufactured by a usual process for manufacturing a CCD solid-stateimaging device.

In actual imaging with the solid-state imaging device 1030 manufactured,the dark current was significantly decreased, and an image withoutsignificant noise was obtained even by imaging under dark conditions.

Alternatively, the single crystal layer may be formed only on thephotodiodes PD using a mask.

For example, the silicon substrate 1011 is covered with a mask exceptportions other than the photodiodes PD, and the surface of the siliconsubstrate 1011 is carbonized. As a result, the single crystal layer isformed only on the photodiodes PD.

FIG. 58 is a drawing (sectional view) showing a schematic configurationof a solid-state imaging device including a single crystal layer formedby a method different from that for the solid-state imaging device shownin FIG. 57.

In FIG. 58, reference numeral 1040 denotes a solid-state imaging device;reference numeral 1002, a vertical CCD register; reference numeral 1011,a silicon substrate; reference numeral 1012, a p-type semiconductor wellregion; reference numeral 1013, a (n-type) charge storage region;reference numeral 1015, a transfer channel region; reference numeral1019, a transfer electrode; reference numeral 1021, a light-shieldingfilm; and reference numeral 1027, a single crystal layer. PD representsa photodiode.

As shown in a sectional view of FIG. 58, the solid-state imaging device1040 is different from that shown in FIG. 57 in that the single crystallayer 1027 is formed on the photodiodes PD so as to enter the siliconsubstrate 1011.

In each of the above-described embodiments, the single crystal layer1025, 1026, or 1027 composed of SiC or SiGeC is formed on the siliconsubstrate 1101. However, another material having a wider band gap thanthat of silicon of the silicon substrate 1101 may be used for the singlecrystal layer.

Examples of a material other then SiC having a wider band gap than thatof silicon are listed below together with the lattice constants. Allmaterials listed below have the same cubic system as silicon Si. This isbecause the same cubic system is preferred for epitaxial growth onsilicon.

Material Band gap Eg (eV) Lattice constant (Å) GaAs 1.43 5.654 AlAs 2.165.66 GaN 3.27 4.55 AlN 6.8 4.45 ZnSe 2.67 5.667 ZnS 3.70 5.41 MgSe 3.65.62 MgS 4.5 5.89

Herein, GaAs, AlAs, GaN, and AlN are group III-V element compoundsemiconductors, and may be used as an AlGaAs ternary mixed crystal orAlGaN ternary mixed crystal. Other group III-V compound semiconductorsinclude an AlGaInP quaternary mixed crystal and the like.

Also, ZnSe and ZnS are group II-VI compound semiconductors and may beused as a ZnMgSSe quaternary mixed crystal. Other group II-VI compoundsemiconductors include a ZnMgO ternary mixed crystal and the like.

The present invention may be applied to a solid-state imaging deviceincluding photoelectric transducers formed in a semiconductor layerother than a silicon layer.

For example, the present invention may be applied to a solid-stateimaging device including photoelectric transducers (photodiodes) formedin a compound semiconductor layer.

In order to detect infrared light in a wavelength region of 0.9 μm to1.7 μm, a compound such as GaInAs is used for a semiconductor layer inwhich photoelectric transducers are formed.

In order to detect infrared light in a wavelength region of 3 μm to 5μm, a compound such as InSb or PtSi is used for a semiconductor layer inwhich photoelectric transducers are formed.

In order to detect infrared light in a wavelength region of 8 μm to 14μm, a compound such as HgCdTe is frequently used for a semiconductorlayer in which photoelectric transducers are formed.

The detection of these wavelength regions permits the invention to beapplied to, for example, a photodiode for silica glass fiber opticalcommunication and a solid-state imaging device (commonly called“infrared thermography”) for obtaining temperature information.

When any one of these materials is used for a semiconductor layer inwhich photoelectric transducers are formed, a single crystal layerhaving a wide band gap is bonded to the surface of a silicon substratebecause of the wide band gap of the material, thereby causing the sameeffect of decreasing the dark current as that of bonding between asilicon substrate and a SiC compound.

The material of the single crystal layer is not limited the compoundsemiconductors, and the invention may be applied to a case in whichphotoelectric transducers (photodiodes) are formed in a semiconductorlayer composed of a group IV element other than silicon, for example,Ge.

In each of the above-described embodiments, the invention is applied toa CCD solid-state imaging device. However, the invention may be appliedto other types of solid-state imaging devices, for example, a CMOSsolid-state imaging device.

FIG. 59 is a drawing (schematic plan view) showing a schematicconfiguration of a solid-state imaging device according to a furtherembodiment of the invention. In this embodiment, the invention isapplied to a CMOS solid-state imaging device.

In FIG. 59, reference numeral 1050 denotes a solid-state imaging device;reference numeral 1051, a cell amplifier; reference numeral 1052, avertical signal line; reference numeral 1053, a horizontal signal line;reference numeral 1054, a shift register; reference numeral 1055, anoise canceling circuit; and reference numeral 1056, a horizontal shiftregister. PD represents a photodiode.

As shown in FIG. 59, the solid-state imaging device 1050 includes thephotodiodes PD serving as light receiving parts which are arranged in amatrix and each of which is connected to the corresponding signal lines1052 and 1053 through the cell amplifier 1051. The signal lines includethe vertical signal lines 1052 connected to the vertical shift register1054, and the horizontal signal lines 1053. The photodiode PD of eachpixel is provided near each of the intersections of the signal lines1052 and 1053.

The horizontal signal lines 1053 are connected to a signal line foroutputting signal voltages through the noise canceling circuit 1055 andMOS transistors shown in a lower portion of the drawing.

The gates of the MOS transistors are connected to the horizontal shiftregister 1056 so that the MOS transistors are turned on and off by thehorizontal shift register 1056.

Although not shown in the drawing, in this embodiment, a single crystallayer is provided on at least the photodiodes PD formed in asemiconductor layer in which the photodiodes PD and the source and drainregions of the MOS transistors are formed, the single crystal layerhaving a wider band gap than that of the semiconductor layer.

As a result, like in each of the above-described embodiments in whichthe invention is applied to the CCD solid-state imaging device, the darkcurrent may be significantly decreased, and even when the pixels of thesolid-state imaging device 1050 is made fine to decrease the quantity ofincident light, a sufficient S/N ratio may be secured. Therefore, asatisfactory image without significant noise may be obtained only byamplification with an amplifier for compensating for low sensitivity.

Therefore, by making the pixels in the solid-state imaging device 1050fine, the number of pixels in the solid-state imaging device 1050 may beincreased, and the solid-state imaging device may be decreased in size.

Furthermore, the invention may be applied not only to a configuration inwhich photoelectric transducers such as photodiodes are arranged in amatrix but also to a configuration in which pixels includingphotoelectric transducers are arranged in a staggered form (checkedpattern) and a configuration in which pixels are arranged in a line or aplurality of lines (line sensor or the like).

The invention may be applied not only to a solid-state imaging devicebut also to a light-receiving device including photodiodes(photoelectric transducers) formed in a single crystal semiconductorlayer.

For example, the invention may be applied to a photodiode, a PINphotodiode, or a Schottky sensor which is used as a high-performancesensor with low noise.

Furthermore, a light receiving device according to an embodiment of theinvention and a light receiving device such as a semiconductor laser ora light-emitting diode may be mounted on a common substrate to form ahybrid structure, or a semiconductor substrate may also be used as asemiconductor layer to form a monolithic optical device.

In order to manufacture a light receiving device or a solid-stateimaging device according to an embodiment of the invention, a step offorming a semiconductor region for forming photoelectric transducers andother semiconductor regions in a semiconductor layer, and a step offorming a polycrystalline layer may be performed in any desired order.

The invention is not limited to the above-described embodiments, andvarious modifications may be made within the range of the gist of theinvention.

<Arrangement of Color Separation Filter; First Example>

FIGS. 41A, 41B, and 41C are drawings showing a first example ofarrangement of color separation filters. In the first example, adetection region for removing visible light and receiving and detectingonly infrared light and a detection region for visible color imaging areprovided.

FIG. 41A shows a mosaic arrangement of respective color filters, i.e., aBayer arrangement of basic color filters. Namely, a pixel part has aconfiguration in which a repeat unit of color separation filters include2×2 pixels so that unit pixels in a square lattice correspond to threecolor filers of red (R), green (G), and blue (B). In order to providethe detection part (detection region) for removing visible light andreceiving and detecting only infrared light, one of two green filters isreplaced by a black filter BK. In other words, the four types of colorfilters having respective filter characteristics are regularly arrangedfor visible color imaging, the color filters including filters for thewavelength regions (color components) of the primary colors R, G, and Band the black filter BK for infrared light different from the componentsof the primary color filters R, G, and B.

For example, first color pixels for detecting a first color (red; R) arearranged in even-numbers rows and odd-numbers columns, second colorpixels for detecting a second color (green; G) are arranged inodd-numbered rows and odd-numbered columns, third color pixels fordetecting a third color (blue; B) are arranged in odd-numbers rows andeven-numbers columns, and fourth color pixels (black correction pixels)for detecting infrared light IR are arranged in even-numbered rows andeven-numbered columns. Therefore, G/B pixels or R/BK pixels are arrangedin a checked pattern. In such a Bayer arrangement of basic colorfilters, G/B or R/BK two colors are repeated in both the row directionand the column direction.

Therefore, a visible color image is obtained by detection with thecorresponding detection region through the primary color filters R, G,and B, and an infrared image is obtained by detection with thecorresponding detection region through the black filter BK independentlyof the visible color image and at the same time as the visible colorimage. The detection portions (detection elements) in which the primarycolor filters R, G, and B are respectively disposed separate a visiblelight region, which is a transmitted wavelength region, into wavelengthsand detects the respective components.

Although, in this example, the primary color filters 14R, 14G, and 14Bare used as colors filters 14 for visible color imaging, complementarycolor filters Cy, Mg, and Ye may be used. The detection portions(detection elements) in which the complementary color filters Cy, Mg,and Ye are respectively disposed separate a visible light region, whichis a transmitted wavelength region, into wavelengths and detects therespective components. In this case, for example, as shown in FIG. 41B,the primary color filters 14R, 14G, and 14B may be replaced by theyellow filter Ye, the magenta filter Mg, and the Cyan filter Cy,respectively. In addition, one of two magenta colors in a diagonaldirection may be replaced by a black filter BK for a correction pixel.

In this case, a dielectric stacked film 1 is formed on each of pixels12Cy, 12Mg, and 12Ye excluding a pixel in which the black filter isdisposed, and the complementary color filters 14Cy, 14Mg, and 14Ye arefurther provided on the respective dielectric stacked films 1. Namely,light components of cyan Cy, magenta Mg, and yellow Ye in visible lightVL are received through the corresponding complementary color filters14Cy, 14Mg, and 14Ye, respectively. Since the dielectric stacked film 1is formed on the detection portion of each of the pixels in which thecomplementary color filters are disposed, there is the function toeffectively cut infrared light.

Instead of a combination of complementary color filters Cy, Mg, and Ye,a combination of a green filter G, which is one of the primary colorfilters, and a white filter W may be used. In this case, pixels of ablack filter BK which serve as correction pixels may also be provided.For example, as shown in FIG. 41C, in a field storage frequencyinterleave system in which two complementary color filters Cy and Mg anda green color filter G as a primary color filter are -combined, one oftwo primary color filters G in four pixels may be replaced by a blackcolor filter BK for correction pixels.

<First Example of Sensor Structure; Corresponding to CCD>

FIGS. 42 and 43 are drawings illustrating a CCD solid-state imagingdevice having the arrangement of color separation filters shown in FIGS.41A, 41B, and 41C so that images of the two wavelength components ofinfrared light IR and visible light VL are separately taken at the sametime. FIG. 42 is a sketch (perspective view) showing an example of astructure, and FIG. 43 is a drawing showing a sectional structure near asubstrate surface. The two drawings show an example of application to aCCD solid-state imaging device 101 using a dielectric stacked film 1.

In the drawings, reference numeral 1 denotes the dielectric stackedfilm; reference numeral 11, a spectral image sensor; and referencenumeral 12, a unit pixel matrix.

In the structure of the CCD solid-state imaging device shown in FIG. 42,only the unit pixel matrix 12 including four pixels is shown. However,in fact, the unit pixel matrix 12 is repeated in the lateral directionand the longitudinal direction.

Among the four pixels in the periodic arrangement of the unit pixelmatrix 12, the dielectric stacked film 1 is not formed in a pixel 12IR,but a black filter 14BK is provided in a pixel 12Ir so that onlyinfrared light IR is received through the black filter 14Bk. Namely, theblack filter 14Bk is used as a color filter 14 in the pixel 12IR forinfrared light IR, and thus visible light VL is cut off, and onlyinfrared light IR is received. The pixel 12IR in which the black filter14Bk is disposed is also referred to as the “black pixel 12BK”.

On the other hand, the dielectric stacked film 1 is provided on each ofthe other pixels 12B, 12G, and 12R, and primary color filters 14R, 14G,and 14B are further provided thereon so that the primary colorcomponents of blue B, green G, and red R in visible light VL arereceived through the corresponding primary color filters 14B, 14G, and14R, respectively. Namely, the dielectric stacked film 1 is formed onthe detection portion of each of the pixels in which the primary colorfilters are respectively disposed, and thus there is the function toeffectively cut off infrared light. The circuit configuration used is asshown in FIG. 29.

FIG. 43 showing a sectional structure near a substrate surface shows apixel which receives only visible light VL. A pixel 12IR which receivesinfrared light IR has a structure not including the dielectric stackedfilm 1 and the black filter 14BK. Namely, as in the manufacturingprocess shown in FIGS. 33A to 33F, a SiN film and a SiO₂ film aresuccessively deposited by a CVD method to form a dielectric stacked filmhaving the structure shown in FIG. 13. Then, the dielectric stacked filmis removed only from a pixel receiving infrared light by lithography anda RIE method. Then, a SiO₂ layer is again deposited to planarize thesurface.

By using an imaging device having the above-described structure, avisible color image based on the primary color components and aninfrared image are simultaneously obtained. In other words, when theblack filter 14BK which absorbs only visible light VL is provided as acolor filter 14C, visible light VL is absorbed by the black color filter14BK, and thus an infrared IR image is obtained on the basis of imagedata from the pixels 12IR for infrared light IR.

<Arrangement of Color Separation Filter; Second Example>

FIGS. 44A, 44B, and 44C are drawings showing a second example ofarrangement of color separation filters. In the second example, adetection region for receiving and detecting all wavelength componentsof visible light together with infrared light and a detection region forvisible color imaging are provided.

FIG. 44A shows a Bayer arrangement of basic color filters. Namely, apixel part has a configuration in which a repeat unit of colorseparation filters include 2×2 pixels so that unit pixels in a squarelattice correspond to three color filers of red (R), green (G), and blue(B). In order to provide the detection part (detection region) forreceiving and detecting all wavelength components of visible lighttogether with infrared light, one of two green filters is replaced of awhite filter W. In other words, the four types of color filters havingrespective filter characteristics are regularly arranged for visiblecolor imaging, the color filters including filters for the wavelengthregions (color components) of the primary colors R, G, and B and thewhite filter W for infrared light different from the components of theprimary color filters R, G, and B.

A white pixel in which the white filter W is disposed transmits allwavelength components ranging from visible light to infrared light(particularly near-infrared light). From this viewpoint, in fact, colorfilters may not be provided.

For example, first color pixels for detecting a first color (red; R) arearranged in even-numbers rows and odd-numbers columns, second colorpixels for detecting a second color (green; G) are arranged inodd-numbered rows and odd-numbered columns, third color pixels fordetecting a third color (blue; B) are arranged in odd-numbers rows andeven-numbers columns, and fourth color pixels (white pixels) fordetecting infrared light IR are arranged in even-numbered rows andeven-numbered columns. Therefore, G/B pixels or R/W pixels are arrangedin a checked pattern. In such a Bayer arrangement of basic colorfilters, G/B or R/W two colors are repeated in both the row directionand the column direction.

Therefore, a visible color image is obtained by detection with thecorresponding detection regions through the primary color filters R, G,and B, and an infrared image or a mixed image of infrared light andvisible light is obtained by detection with the corresponding detectionregion through the white filter W independently of the visible colorimage and at the same time as the visible color image. For example, byusing pixel data from the pixels 12IR which receive a mixed component ofvisible light VL and infrared light IR, an image of the mixed componentof visible light VL and infrared light IR is obtained, and thesensitivity is increased. Also, both an image of the mixed component ofvisible light VL and infrared light IR and a visible VL image areobtained. However, only an infrared IR image may be obtained using adifference between both images.

Although, in this example, the primary color filters 14R, 14G, and 14Bare used as colors filters 14 for visible color imaging, complementarycolor filters Cy, Mg, and Ye may be used. In this case, for example, asshown in FIG. 44B, the primary color filters 14R, 14G, and 14B may bereplaced by the yellow filter Ye, the magenta filter Mg, and the cyanfilter Cy, respectively. In addition, one of two magenta colors in adiagonal direction may be replaced by a white filter W for infraredimaging.

In this case, a dielectric stacked film is formed on each of pixels12Cy, 12Mg, and 12Ye excluding a pixel in which the white filter isdisposed, and the complementary color filters 14Cy, 14Mg, and 14Ye arefurther provided on the respective dielectric stacked films 1. Namely,light components of cyan Cy, magenta Mg, and yellow Ye in visible lightVL are received through the corresponding complementary color filters14Cy, 14Mg, and 14Ye, respectively. Since the dielectric stacked film 1is formed on the detection portion of each of the pixels in which thecomplementary color filters are disposed, there is the function toeffectively cut infrared light.

Instead of a combination of complementary color filters Cy, Mg, and Ye,a combination of a green filter G, which is one of the primary colorfilters, and a complementary filter may be used. In this case, pixels ofa white filter W which serve as correction pixels may also be provided.For example, as shown in FIG. 44C, in a field storage frequencyinterleave system in which two complementary color filters Cy and Mg anda green color filter G as a primary color filter are combined, one oftwo primary color filters G in four pixels may be replaced by a whitecolor filter W for correction pixels.

Since the white correction pixels 12W have sensitivity in a widewavelength region from visible light VL and infrared light IR, a signalis easily saturated as compared with pixels for visible color imaging(pixel in which a primary color filter is disposed), and the saturationphenomenon becomes a problem, particularly, in imaging in a brightenvironment. Specifically, in a bright environment, a proper infraredimage is not obtained.

In order to solve the problem of saturation, the detection time of thedetection part in which the white filter W is disposed may be controlledby the drive control part 146. For example, in a bright environment,high-speed imaging may be performed by exposure control using a shutterfunction (including a mechanical shutter and an electronic shutter). Forexample, exposure of an imaging device may be performed with a shortperiod to read pixel signals from the imaging device (particularly, thedetection part), and the pixel signals may be transmitted to the imagesignal processing part 140.

In this case, exposure and signal reading are performed at a rate higherthan, for example, 60 frames/second, to cause an increased effect on thesaturation. Alternatively, signal reading may be simply performed withina time (storage time) shorter than 0.01667 second. In this case, chargesignals may be discharged to the substrate side using overflow so thatstored charges are effectively read within a short time.

More preferably, exposure and signal reading are performed at a ratehigher than 240 frames/second to further improve the effect on thesaturation. Alternatively, signal reading may be simply performed withina time (storage time) shorter than 4.16 milliseconds.

The pixels from which charges are read within a short time (storagetime) so as to prevent saturation may be limited to the correction whitepixels 12W or may be all pixels including the other pixels (primarycolor pixels in which the primary color filters are respectivelydisposed) for visible color imaging.

Alternatively, signals read within a short exposure time may beintegrated two times to convert weak signals in a dark place to strongsignals, thereby increasing the S/N ratio. In this case, for example,proper sensitivity and a high S/N ratio are obtained by imaging in botha dark environment and a bright environment, thereby extending thedynamic range. Namely, saturation in the white correction pixels 12W isprevented by high-speed imaging, and a wide dynamic range is achieved byintegration of signals.

<Second Example of Sensor Structure; Corresponding to CCD>

FIG. 45 is a drawing illustrating a CCD solid-state imaging device whichhas the arrange of color separation filters shown in FIGS. 44A, 44B, and44C so that images of two wavelength components of visible light VL andinfrared light IR are separately obtained at the same time. FIG. 45 is asketch (perspective view) which shows an example of application to a CCDsolid-state imaging device 101 using a dielectric stacked film. Asectional structure near a substrate surface is the same as in FIG. 43.

In the structure of the CCD solid-state imaging device 101 shown in FIG.45, only a unit pixel matrix 12 including four pixels is shown. However,in fact, the unit pixel matrix 12 is repeated in the lateral directionand the longitudinal direction.

Among the four pixels in the periodic arrangement of the unit pixelmatrix 12, the dielectric stacked film 1 is not formed in a pixel 12IR,and a color filter 14 is not provided in a pixel 12Ir so that infraredlight IR is received without being passed through the color filter 14.In this case, the pixels 12IR receive a mixed component of infraredlight IR and visible light VL. The pixels 12IR in each of which thecolor filter 14 is not provided are referred to as “white pixels 12W” or“whole-range transmitting pixels”.

In each of the pixels 12IR in which the dielectric stacked film 1 is notformed, the color filter 14 is not disposed in the white pixel 12W sothat both infrared light IR and visible light VL simultaneouslycontribute to signals. In this case, the pixels 12IR for infrared lightIR function as pixels not only for infrared light IR but also for bothinfrared light IR and visible light VL.

On the other hand, the dielectric stacked film 1 is provided on each ofthe other pixels 12B, 12G, and 12R, and primary color filters 14R, 14G,and 14B are further provided thereon so that the primary colorcomponents of blue B, green G, and red R in visible light VL arereceived through the corresponding primary color filters 14B, 14G, and14R, respectively. Namely, the dielectric stacked film 1 is formed onthe detection portion of each of the pixels in which the primary colorfilters are respectively disposed, and thus there is the function toeffectively cut off infrared light. As the primary color filters 14R,14G, and 14B used in the second embodiment, the first example shown inFIG. 46A may be used. The circuit configuration used is as shown in FIG.29.

By using an imaging device having the above-described structure, avisible color image based on the primary color components and aninfrared IR image or a mixed image of infrared light IR and visiblelight VL are simultaneously obtained. For example, an image of a mixedcomponent of infrared light IR and visible light VL may be obtainedusing pixel data from the pixels 12IR which receive a mixed component ofinfrared light IR and visible light VL, thereby increasing thesensitivity. Also, both an image of a mixed component of infrared lightIR and visible light VL and a visible VL image are obtained, but only aninfrared IR image may be obtained by using a difference between bothimages.

Although not shown in the drawing, a white filter 14W may be replaced bya green filter which transmits a G color component in the visible regionand an infrared component and cuts off the other components (B componentand R component in the visible region). Namely, a detection region forreceiving and detecting infrared light and a specified wavelengthcomponent in visible light may be provided.

In this case, an image of a mixed component of infrared light IR and aspecified wavelength component in visible light VL may be obtained usingpixel data from the pixels 12IR which receive a mixed component ofinfrared light IR and the specified wavelength component in visiblelight VL, thereby increasing the sensitivity. Also, both an image of amixed component and a visible VL image are obtained, but only aninfrared IR image may be obtained by using a difference between infraredlight IR and the specified wavelength component in visible light VL.

<Other Examples of Arrangement of Color Separation Filter>

FIGS. 46 to 52 are drawings illustrating a pixel arrangement consciousof a decrease in resolution. With respect to a pixel arrangement, whenthe arrangement shown in FIGS. 41 or 44 is used, pixels for detectinginfrared light (or mixture of infrared light and visible light) areadded to pixels for visible light in which RGB ordinary primary colorfilters or CyMgYe complementary color filters (or a primary color filterG) are disposed.

For example, green pixels G or magenta pixels Mg for visible colorimaging are replaced by black correction pixels, white pixels, greencorrection pixels, or magenta correction pixels, thereby possiblydecreasing resolution of any of a visible color image and an infraredimage. For example, when one G pixel in an ordinary Bayer arrangement isreplaced by a red pixel, resolution is decreased. However, when acorrection pixel and a pixel (for example, a green pixel G) for awavelength component which greatly contributes to resolution areappropriately arranged, the problem of resolution may be resolved.

In this case, it is important that like in a ordinary structure, in acolor separation filter arrangement in which color filters are arrangedin a mosaic pattern, pixels for infrared light (for mixture of infraredlight and visible light) may be arranged in a mosaic pattern with apredetermined lattice spacing, and pixels of one color of primary colorsRGB of visible light or complementary colors Cy, Mg, and Ye may bearranged in a mosaic pattern with a predetermined lattice spacing.

The mosaic pattern means that pixels of one color are arranged in alattice form with a predetermined lattice spacing, and pixels of onecolor may not be adjacent to each other. In a typical example of a pixelarrangement in which pixels of one color are adjacent to each other,square pixels of infrared light and square pixels of other colors arealternatively arranged in a grid pattern (checked pattern).Alternatively, square pixels of one of the primary colors RGB of visiblelight or one of the complementary colors CyMgYe and squired pixels ofthe other colors are alternately arranged in a grid pattern (checkedpattern).

<Example of Application to Primary Color Filter>

For example, in order to suppress a decrease in resolution of a visiblecolor image using RGB primary color filters, the arrangement density ofG pixels in the visible region may be maintained, and pixels of R or Bof the visible region may be replaced by correction black pixels, whitepixels, or green pixels. For example, as shown in FIGS. 46A and B, in a2×2 unit pixel matrix 12 including, color pixels G for detecting a greencomponent in the visible region are arranged in odd-numbered rows andodd-numbered columns and even-numbered rows and even-numbered columns,and correction black pixels (FIG. 46A), white pixels (FIG. 46B), orgreen pixels (not shown) are arranged in even-numbered rows andodd-numbered columns.

In addition, in the unit pixel matrixes 12 in an odd-numbered column,color pixels B for detecting a blue component in the visible region aredisposed at an odd-numbered row and at even-numbered column in anodd-numbered unit pixel matrix 12 in the column direction, and colorpixels R for detecting a red component of the visible region arearranged disposed at an odd-numbered row and at even-numbered column inan even-numbered unit pixel matrix 12 in the column direction. In theunit pixel matrixes 12 in an even-numbered column, the color pixels band the color pixels R are disposed in an arrangement opposite to theabove. As a whole, the repeat cycles of the color filters 14 arecompleted by the 2×2 unit pixel matrix 12.

In the arrangement shown in FIGS. 46A and 46B, pixels of one of theprimary colors RGB of visible light and pixels of the other colors arealternately arranged in a checked pattern. In this arrangement, thedensity of color pixels G greatly contributing to the resolution of avisible color image may be set to the same as in a Bayer arrangement,thereby preventing a decrease in resolution of a visible color image.

However, the arrangement density of color pixels R and color pixels B is½ of that of the Bayer arrangement, and thus color resolution isdecreased. However, human visibility for red R and blue B is lower thanthat for green G, the decrease in color resolution is not a largeproblem. On the other hand, in an infrared image using correctionpixels, the arrangement density of the correction pixels is ½ of that ofcolor pixels G for detecting a green component in the visible region,and thus the resolution is lower than that of a visible color image.

For example, a CMOS solid-state imaging device (pixel circuitconfiguration shown in FIG. 31) having the layer structure shown in FIG.31 (sectional structure corresponding to pixels for receiving visiblelight being as shown in FIG. 35) was experimentally manufactured by themanufacturing process shown in FIGS. 33A to 33F. In the CMOS solid-stateimaging device, a black filter 14BK having the transmission spectralcharacteristics shown in FIG. 47 was used, and black correction pixelswere arranged in the pattern shown in FIG. 46A. As a result, it wasfound that a high-resolution color image of the primary colors and aninfrared image with relatively high resolution lower than that of thecolor image are simultaneously obtained.

In addition, a CMOS solid-state imaging device (pixel circuitconfiguration shown in FIG. 31) having the layer structure shown in FIG.37 (sectional structure corresponding to pixels for receiving visiblelight being as shown in FIG. 35) was experimentally manufactured by themanufacturing process shown in FIGS. 33A to 33F. In the CMOS solid-stateimaging device, white pixels were arranged in the pattern shown in FIG.46B. As a result, it was found that a high-resolution color image of theprimary colors and an image of a mixed component of infrared light andvisible light are simultaneously obtained, the image of the mixedcomponent having relatively high resolution lower than that of the colorimage. It was also found that an infrared image is simultaneouslyobtained by decreasing the intensity of blue, red, and green detected bythe primary color pixels R, G, and B, respectively, for visible light.

In order to prevent saturation, all pixels may be exposed within a shorttime to read charge signals, and signals read within a shorter time maybe integrated two times, thereby converting to large signals. Therefore,even in a dark environment or bright environment, proper sensitivity isobtained, and the dynamic range is extended.

Furthermore, a structure in which such a black correction pixel as shownin FIG. 46A and a multilayer film are combined, or a structure in whichsuch a white pixel as shown in FIG. 46B and a multilayer film arecombined exhibits the same effect on the CCD structure shown in FIG. 43and on the CMOS solid-state imaging device.

In order to suppress a decrease in resolution of an infrared image, asshown in FIGS. 48A and 48B, color pixels G for detecting a greencomponent of the visible region shown in FIG. 46A may be interchangedwith correction black pixels (FIG. 48A), white pixels (FIG. 48B), orgreen pixels (not shown). In this case, infrared pixels as correctionpixels and pixels of the other colors are alternately arranged in achecked pattern. In this arrangement, the density of the correctionpixels may be set to the same as in a Bayer arrangement, therebypreventing a decrease in resolution of an infrared image. However, thearrangement density of color pixels G greatly contributing to theresolution of a visible color image is ½ of that of the correctionpixels, and thus the resolution of a visible color image is lower thanthat of an infrared image. The color resolution is the same as in FIGS.46A and 46B.

For example, a CMOS solid-state imaging device (pixel circuitconfiguration shown in FIG. 29, and a sectional structure correspondingto pixels for receiving visible light being as shown in FIG. 43) wasexperimentally manufactured. In the CMOS solid-state imaging device, ablack filter 14BK exhibiting the transmission spectral characteristicsshown in FIG. 47 was used, and black correction pixels were arranged inthe pattern shown in FIG. 48A. As a result, it was found that ahigh-resolution infrared image and a visible color image with relativelyhigh resolution lower than that of an infrared image are simultaneouslyobtained.

In addition, a CMOS solid-state imaging device (pixel circuitconfiguration shown in FIG. 29, and a sectional structure correspondingto pixels receiving visible light being as shown in FIG. 43) wasexperimentally manufactured. In the CMOS solid-state imaging device,white correction pixels were arranged in the pattern shown in FIG. 46B.As a result, it was found that a high-resolution image of a mixedcomponent of infrared light and visible light is obtained. It was alsofound that an infrared image is obtained by decreasing the intensity ofblue, red, and green detected by the primary color pixels R, G, and B,respectively, for visible light, and, at the same time, a visible colorimage with relatively high resolution lower than that of an infraredimage is obtained.

It was further confirmed that in either of the imaging devices, imagingwith high color reproducibility is performed even in an infraredenvironment without using an infrared cut filter. It was further foundthat in the structure using the white pixels, luminance signals obtainedon the basis of a visible image of the primary colors are correctedusing a visible component obtained from the white pixels, therebyfurther improving the sensitivity of a visible color image independentlyof color reproducibility.

In order to prevent saturation, charges of only the white pixels may beread within a short time using overflow, and signals read within ashorter time may be integrated two times, thereby converting to largesignals. Therefore, even in a dark environment or bright environment,proper sensitivity is obtained, and the dynamic range is extended.

Furthermore, a structure in which such a black correction pixel as shownin FIG. 48A and a multilayer film are combined, or a structure in whichsuch a white pixel as shown in FIG. 48B and a multilayer film arecombined exhibits the same effect on the CCD structure shown in FIG. 43and on the CMOS solid-state imaging device.

FIGS. 49A, 49B, and 49C are drawings illustrating other examples of apixel arrangement in which pixels for obtaining an infrared image areprovided independently of a visible color image. In these examples, aplurality of color filters is combined for a pixel for obtaining aninfrared image. For example, the examples shown in each of FIGS. 49A,49B, and 49C, the first and second examples are combined, and in a unitpixel matrix 12, a black filter 14BK and a white filter 14W arealternately arranged for pixels for obtaining an infrared image. FIG.49A shows a combination of FIGS. 41 and 44, FIG. 49B shows a combinationof FIGS. 46A and 46B, and FIG. 49C shows a combination of FIGS. 48A and48B.

In an arrangement including each of these combinations, for example,white pixels 12W are mainly used for increasing sensitivity, and blackpixels 12Bk are used for maintaining normal illumination and highillumination. By combining the outputs of both types of pixels, a widerange of reproduction ranging from a low illumination level to a highillumination level may be achieved, and the dynamic range may be alsoextended.

<Example of Application to Complementary Filter>

In order to suppress a decrease in resolution of a visible color imageusing CyMgYe complementary color filters, the arrangement density of Mgpixels in the visible region may be maintained, and pixels of R or B ofthe visible region may be replaced by correction black pixels, whitepixels, or green pixels for obtaining an infrared image. For example, asshown in FIGS. 50A and B, in a 2×2 unit pixel matrix 12, color pixels Mgfor detecting a magenta component in the visible region are arranged atan odd-numbered row and an odd-numbered column and an even-numbered rowand an even-numbered column, and black pixels (FIG. 50A), white pixels(FIG. 50B), or magenta pixels (not shown) for obtaining an infraredimage are arranged in an even-numbered row and an odd-numbered column.In addition, one of magenta pixels Mg may be replaced by a green pixelG.

In this case, pixels Mg one of the complementary colors Cy, Mg, and Yeof visible light and pixels of the other colors are alternately arrangedin a checked pattern. In this arrangement, the density of the colorpixels Mg greatly contributing to the resolution of a visible colorimage may be set to the same as in a Bayer arrangement, therebypreventing a decrease in resolution of a visible light image.

However, the arrangement density of color pixels Cy and Ye is ½ of thatof the color pixels Mg, and thus the color resolution is decreased.However, human visibility for color is low, and thus the decrease incolor resolution is not a large problem. On the other hand, in aninfrared image using correction pixels, the arrangement density of thecorrection pixels (infrared pixels) is ½ of that of color pixels Mg fordetecting a magenta component in the visible region, and thus theresolution is lower than that of a visible color image.

In order to suppress a decrease in resolution of an infrared image, asshown in FIGS. 51A and 51B, color pixels Mg for detecting a magentacomponent of the visible region may be interchanged with correctionblack pixels (FIG. 51A), white pixels (FIG. 51B), or magenta colorpixels (not shown) for obtaining an infrared image. In this case,infrared pixels as correction pixels and pixels of the other colors arealternately arranged in a checked pattern. In this arrangement, thedensity of the correction pixels may be set to the same as in a Bayerarrangement, thereby preventing a decrease in resolution of an infraredimage. However, the arrangement density of color pixels Mg greatlycontributing to the resolution of a visible color image is ½ of that ofthe correction pixels, and thus the resolution of a visible color imageis lower than that of an infrared image. The color resolution is thesame as in FIGS. 50A and 50B.

Although, in the above-described arrangements for suppressing a decreasein resolution, the green G or magenta Mg pixels are arranged at as ahigh density as possible in a mosaic pattern (in a typical example, achecked pattern), the pixels of the other colors (for example, R and B,or Cy and Ye) may be arranged in a checked pattern. In this case,substantially the same effect may be obtained. Of course, in order toincrease resolution and color resolving power, a filter of a colorcomponent with high visibility is preferably arranged at a as highdensity as possible in a mosaic pattern.

<Example of Application to Oblique Arrangement>

Although, in the above examples, color filters are arranged in a squarelattice form, color filters may be arrange in an oblique lattice form.For example, in the arrangement shown in FIG. 52A, the arrangement shownin FIG. 46B is rotated clockwise by 45 degrees. In the arrangement shownin FIG. 53B, the arrangement shown in FIG. 48B is rotated clockwise by45 degrees. In this way, in an oblique arrangement, the pixel density isincreased in both the vertical direction and the horizontal direction,thereby further increasing resolution in both directions.

Although the invention is described with reference to the embodiments,the technical field of the invention is not limited to theabove-described embodiments, and various changes or modifications may bemade within the range of the gist of the invention. These changes ormodifications may be included in the technical field of the invention.

Also, the invention is not limited to the embodiments, and allcombinations described in the embodiments may not be used for resolvingthe problems. Each of the above-described embodiments includes variousmodifications, the plurality of features described may be used in anydesired combination. Some of the features described in the embodimentsmay be removed as long as the effect of the invention is obtained.

The above-described structures are only embodiments of the invention,and as described above, another similar structure may be used forpermitting wavelength spectral separation using a stacked member(dielectric stacked film) having a structure in which a plurality oflayers having different refractive indexes between the adjacent ones andeach having a predetermined thickness, the stacked member also havingthe characteristic that a predetermined wavelength component of anelectromagnetic wave is reflected, and the remainder is transmitted.

Furthermore, the above-described technique is not limited to a techniquefor dispersing into visible light and infrared light. For example, lightmay be dispersed into visible light and ultraviolet light and detected,and ultraviolet light may be detected together with visible light toform an image. Furthermore, an image of visible light simultaneouslydetected is not limited to monochrome image without dispersion, and acolor image may be detected by dispersing a visible band into the threeprimary color components using color filters for the respective colors,as described above.

Therefore, information of ultraviolet light which is invisible with theeyes may be simultaneously obtained together with a visible image(monochrome image or color image) which is visible with the eyes. As aresult, the invention may be also applied to a key device of a newinformation system such as an optical synthesis monitoring camera or thelike.

For example, by using a dielectric stacked film 1 for visible light VLas a reflected wavelength region component and a wavelength side (forexample, ultraviolet light) lower than visible light VL as a transmittedwavelength region component, dispersion into visible light VL and awavelength side lower than visible light VL and detection thereof may beperformed.

Although not shown in the drawings, in the arrangement shown in FIGS.41A to 41C, a dielectric stacked film 1 for reflecting a component at awavelength longer than that of v visible light VL may be formed on apixel 12IR of the four pixels in the periodic arrangement of the unitpixel matrix 12 so that light (ultraviolet light) on the wavelength sideshorter than visible light VL is received. In addition, a dielectricstacked film 1 is not formed on each of the other three pixels 12B, 12G,and 12R, but color filters 14 (14R, 14G, and 14B) are provided thereonso that the three primary color components of blue B, green G, and red Rin the visible light VL are received together with the lower wavelengthside (ultraviolet light).

In order to obtain signals of visible light VL as the reflectedwavelength region component which are substantially not affected by thetransmitted wavelength region component, arithmetic operation ispreferably performed between the ultraviolet component as thetransmitted wavelength region component and the reflected wavelengthregion component. As the color filters 14 (14R, 14G, and 14B), colorfilters having substantially zero transmittance of the ultraviolet lightas the transmitted wavelength region component may be used. In thiscase, a component on the wavelength side (ultraviolet light) lower thanvisible light VL is cut off by the color filters (14R, 14G, and 14B),thereby eliminating arithmetic operation.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

1. A method for acquiring physical information using a device fordetecting a physical distribution for a predetermined purpose on thebasis of unit signals, the device including, as unit components, adetecting part for detecting an electromagnetic wave and a unit signalgenerating part for generating a corresponding unit signal on the basisof the quantity of the electromagnetic wave detected by the detectingpart and outputting the unit signal, and the unit components beingdisposed on the same substrate in a predetermined order; wherein thedetecting part includes a stacked member having a structure in which aplurality of layers having different refractive indexes between theadjacent ones and each a predetermined thickness is stacked, the stackedmember being provided on the incident surface side to which theelectromagnetic wave is incident and having the characteristic that apredetermined wavelength region component of the electromagnetic wave isreflected, and the reminder is transmitted; and the transmittedwavelength region component transmitted through the stacked member isdetected by the detecting part, and the physical information for apredetermined purpose is acquired on the basis of the unit signal of thetransmitted wavelength region component obtained from the unit signalgenerating part wherein the stacked member is not provided on theincident surface side to which the electromagnetic wave is incident in adetecting part other than the detecting part for the transmittedwavelength region component so that the reflected wavelength regioncomponent is detected by the other detecting part, thereby obtainingphysical information for a second predetermined purpose on the basis ofa unit signal of the reflected wavelength region component obtained fromthe unit signal generating part.
 2. The method according to claim 1,wherein one of first physical information based on the unit signal ofthe transmitted wavelength region component and second physicalinformation based on the unit signal of the reflected wavelength regioncomponent is selected and output, or both are simultaneously output. 3.The method according to claim 1, further comprising optical membersprovided on the respective incident surface sides of a plurality ofdetecting parts for detecting the transmitted wavelength regioncomponent, for separating the transmitted wavelength region componentinto different wavelength region components; wherein the respectivetransmitted wavelength region components are detected by the pluralityof detecting parts, respectively, and other physical information on thetransmitted wavelength region component is acquired by combining theunit signals of the respective transmitted wavelength region components,which are obtained from the unit signal generating part.
 4. The methodaccording to claim 3, wherein as the optical members, primary colorfilters in which transmitted light in the visible region includes thewavelength components of the three primary colors are used.
 5. Themethod according to claim 3, wherein as the optical members,complementary color filters in which transmitted light in the visibleregion includes complementary colors of the respective three primarycolors are used.
 6. The method according to claim 1, wherein physicalinformation in which the influence of the transmitted wavelength regioncomponent is negligible is obtained as the second physical informationby differential processing of the unit signal of the reflectedwavelength region component and the unit signal of the transmittedwavelength region component.
 7. The method according to claim 6,comprising: providing an optical member on the incident surface side towhich the electromagnetic wave is incident in the detecting part fordetecting the transmitted wavelength region component, for transmittinga predetermined wavelength component of the transmitted wavelengthregion component; providing an optical member on the incident surfaceside to which the electromagnetic wave is incident in the otherdetecting part for detecting the reflected wavelength region component,for transmitting the reflected wavelength region component and thepredetermined wavelength component of the transmitted wavelength regioncomponent; and detecting the predetermined wavelength component of thetransmitted wavelength region component and a composite component of thereflected wavelength region component and the predetermined wavelengthcomponent of the transmitted wavelength region component by therespective detecting parts to obtain physical information as the secondphysical information in which the influence of the transmittedwavelength region component is negligible on the basis of the unitsignals of the different wavelength region components obtained from theunit signal generating part.
 8. The method according to claim 1,comprising providing an optical member on the incident surface side towhich the electromagnetic wave is incident in the other detecting partfor detecting the reflected wavelength region component, fortransmitting the reflected wavelength region component and cutting offthe transmitted wavelength region component; and detecting the reflectedwavelength region component excluding the transmitted wavelength regioncomponent by the detecting part to obtain physical information as thesecond physical information in which the influence of the transmittedwavelength region component is negligible on the basis of the unitsignal of the reflected wavelength region component obtained from theunit signal generating part.
 9. An apparatus for acquiring physicalinformation using a device for detecting a physical distribution for apredetermined purpose on the basis of unit signals, the deviceincluding, as unit components, a detecting part for detecting anelectromagnetic wave and a unit signal generating part for generating acorresponding unit signal on the basis of the quantity of theelectromagnetic wave detected by the detecting part and outputting theunit signal, and the unit components being disposed on the samesubstrate in a predetermined order, the apparatus comprising: a stackedmember disposed on the incident side of the detecting part on which theelectromagnetic wave is incident, having a structure in which aplurality of layers having different refractive indexes between theadjacent ones and each having a predetermined thickness is stacked, andalso having the characteristic that a predetermined wavelength regioncomponent of the electromagnetic wave is reflected, and the reminder istransmitted; and a signal processing part for acquiring physicalinformation for a first predetermined purpose on the basis of the unitsignal of a transmitted wavelength region component detected by thedetecting part and transmitted through the stacked member, the unitsignal being obtained from the unit signal generating part, and whereinthe signal processing part acquires physical information for a secondpredetermined purpose on the basis of a unit signal of the reflectedwavelength region component which is obtained from the unit signalgenerating part on the basis of the reflected wavelength regioncomponent which is detected by a sensing part other than a sensing partfor detecting the transmitted wavelength region component, the reflectedwavelength region component being not transmitted through the stackedmember.
 10. The apparatus according to claim 9, wherein the stackedmember is integrated with the detecting part.
 11. The apparatusaccording to claim 9, further comprising a signal switching control partfor controlling the signal processing part so that one of first physicalinformation based on the unit signal of the transmitted wavelengthregion component and second physical information based on the unitsignal of the reflected wavelength region component is selected andoutput, or both are simultaneously output.
 12. The apparatus accordingto claim 9, further comprising optical members provided on therespective incident surface sides of a plurality of detecting parts fordetecting the transmitted wavelength region component, for separatingthe transmitted wavelength region component into respective wavelengthregion components; wherein on the basis the respective transmittedwavelength region components detected by the plurality of detectingparts, respectively, the signal processing part obtains other physicalinformation on the transmitted wavelength region component by combiningthe unit signals of the respective transmitted wavelength regioncomponents, which are obtained from the unit signal generating part. 13.The apparatus according to claim 12, wherein as the optical members areprimary color filters in which transmitted light in the visible regionincludes the wavelength components of the three primary colors.
 14. Theapparatus according to claim 12, wherein the optical members arecomplementary color filters in which transmitted light in the visibleregion includes complementary colors of the respective three primarycolors.
 15. The apparatus according to claim 9, wherein the signalprocessing parts acquires physical information as the second physicalinformation in which the influence of the transmitted wavelength regioncomponent is negligible by differential processing of the unit signal ofthe reflected wavelength region component and the unit signal of thetransmitted wavelength region component.
 16. The apparatus according toclaim 15, further comprising: an optical member on the incident surfaceside to which the electromagnetic wave is incident in a detecting partfor detecting the transmitted wavelength region component, fortransmitting a predetermined wavelength component of the transmittedwavelength region component; and an optical member on the incidentsurface side to which the electromagnetic wave is incident in anotherdetecting part for detecting the reflected wavelength region component,for transmitting the reflected wavelength region component and thepredetermined wavelength component of the transmitted wavelength regioncomponent; and wherein the signal processing part acquires physicalinformation as the second physical information in which the influence ofthe transmitted wavelength region component is negligible bydifferential processing between the unit signal of the predeterminedwavelength component of the transmitted wavelength region componentobtained from the unit signal generating part on the basis of thepredetermined wavelength component transmitted wavelength regioncomponent, and the unit signal of the composite component obtained fromthe unit signal generating part on the basis of the reflected wavelengthregion component and the predetermined wavelength component of thetransmitted wavelength region component.
 17. The apparatus according toclaim 9, further comprising an optical member on the incident surfaceside to which the electromagnetic wave is incident in the detecting partfor detecting the reflected wavelength region component, fortransmitting the reflected wavelength region component and cutting offthe transmitted wavelength region component; wherein the signalprocessing part acquires physical information as the second physicalinformation in which the influence of the transmitted wavelength regioncomponent is negligible using the unit signal of the reflectedwavelength region component obtained from the unit signal generatingpart on the basis of the reflected wavelength region component excludingthe transmitted wavelength region component.
 18. The apparatus accordingto claim 9, wherein the material of the jth layer constituting thestacked member satisfies the following conditional expression (A):0.9×λ0/4n ≦dj1.1×λ0/4n  (A) wherein dj is the thickness, λ0 is thecenter wavelength of the reflected wavelength region component.
 19. Theapparatus according to claim 9, wherein the center wavelength λ0 of thereflected wavelength region component satisfies the followingconditional expression (B):780 nm≦λ0≦1100 nm  (B).
 20. The apparatus according to claim 19, whereinthe center wavelength λ0 of the reflected wavelength region component isabout 900 nm.
 21. The apparatus according to claim 9, wherein when thetransmitted wavelength region λ1 satisfies the conditional expression(C1) below, the material of the layer γ in the stacked member providedon the detecting part side satisfies the conditional expression (C2)below380 nm≦λ1≦780 nm  (C1)0 nm<dγ96 nm  (C2).
 22. The apparatus according to claim 9, wherein thematerial of the layer γ satisfies the conditional expression (C3) below.47 nm<dγ≦96 nmtm (C3).
 23. The apparatus according to claim 9, whereinthe stacked member includes at least two layer materials selected fromoxides such as silicon nitride, silicon oxide, alumina, zirconia,titanium oxide, magnesium oxide, and zinc oxide; polymer materials suchas polycarbonate and acrylic resins; and semiconductor materials such assilicon carbide and germanium Ge.
 24. The apparatus according to claim23, wherein the stacked member includes silicon nitride as a first layermaterial, and silicon oxide as a second layer material.
 25. Theapparatus according to claim 10, wherein the stacked member includes awiring layer provided on the detecting part side, the wiring layer usedfor forming a single line for reading the unit signals from the unitsignal generating part; and a stacked film having a structure in which aplurality of layers having different refractive indexes between adjacentones and each having a predetermined thickness is stacked, and havingthe characteristic that a predetermined wavelength component of theelectromagnetic wave is reflected, and the remainder is transmitted. 26.The apparatus according to claim 25, wherein the stacked film has astructure including silicon nitride as a first layer material andsilicon oxide as a second layer material, the first layer material isdisposed on both outer sides, and both layer materials arte alternatelystacked to a total of nine or more layers, the distance between thestacked film and the detecting part being about 700 nm.
 27. Theapparatus according to claim 25, wherein the stacked film has astructure including silicon nitride as a first layer material andsilicon oxide as a second layer material, the first layer material isdisposed on both outer sides, and both layer materials are alternatelystacked to a total of nine or more layers, the distance between thestacked film and the detecting part being about 3.2 nm.
 28. Theapparatus according to claim 9, further comprising a drive part forcontrolling the detection time of the other detecting part.
 29. Theapparatus according to claim 9, wherein the signal processing partintegrates several times the unit signal of the reflected wavelengthregion component detected by the other detecting part to acquirephysical information for the second predetermined purpose using theintegrated unit signal of the reflected wavelength region component. 30.The apparatus according to claim 9, wherein the detecting part fordetecting the transmitted wavelength region component and the detectingpart for detecting the reflected wavelength region component areperiodically disposed at a constant numerical ratio.
 31. The apparatusaccording to claim 30, wherein one detecting part for detecting thereflected wavelength region component is disposed relative to aplurality of detecting parts for detecting the transmitted wavelengthregion component.
 32. The apparatus according to claim 9, wherein thedetecting part for detecting the transmitted wavelength region componentand the detecting part for detecting the reflected wavelength regioncomponent are disposed at 1:1.
 33. The apparatus according to claim 9,wherein the detecting part for detecting the transmitted wavelengthregion component further includes a combination of a plurality ofdetecting elements for separating the transmitted wavelength regioncomponent into wavelength components and detecting the components, andthe plurality of detecting elements of the detecting part for detectingthe transmitted wavelength region component and the detecting part fordetecting the reflected wavelength component are arranged in atwo-dimensional lattice form so that the detecting elements fordetecting a predetermined wavelength component in the plurality ofdetecting element are arranged in a checked pattern.
 34. The apparatusaccording to claim 9, wherein the detecting part for detecting thetransmitted wavelength region component further includes a combinationof a plurality of detecting elements for separating the transmittedwavelength region component into wavelength components and detecting thecomponents, and the plurality of detecting elements of the detectingpart for detecting the transmitted wavelength region component and thedetecting part for detecting the reflected wavelength component arearranged in a two-dimensional lattice form so that the detecting partsfor detecting the reflected wavelength region component are arranged ina checked pattern.